Hullo! 
I thought I'd make a list of the changes that FroYo(DDJP6) brings about, since I've noticed a few questions being asked about it and I couldn't find a thread related to it(maybe my Search terms were different)
So far, these are what I've noticed, and I will keep adding to them:
==========================================================
1. TouchWiz now has pinch-to-zoom
2. Swype has a 'move-cursor-to-edit' option. Click on text and you'll get a small indicator of the cursor's current position
3. You can take Screenshots. Hold the "Back" button for a second and then press the "Home" button.
4. When you push the "Power" key for a couple of seconds, you'll see an added option - "Data network mode", along with the previously existing "Power Off" mode.
5. USSD Codes (*111#, *123#, etc.) will now run without having to switch off the "Mobile Tracker", helps with viewing your available Credit Balance!
6. Swype's word-prediction has gone for a toss, although usage over a few days will get it back in shape, predicting the words you mostly use once again.
7. Browsing lenghty menus (e.g. message list, Contact list) is faster than before, as compared to the stock Eclair (unrooted, no lagfix). However the App Drawer seems to be a little jerky, but I think that might be because of my version of LauncherPro Plus (0.8.1.1)
8. New Widgets have been added (e.g. News & Weather, Dual Clock, Market, Home Screen Tips, etc.)
9. The "Task Manager" that comes pre-installed (at least it was in mine) now has a separate tab for "RAM Manager" which lets you clear memory at 2 Levels.
10. "Samsung Keypad" now has a "Voice-to-Text" input option available.
11. Skype works.
12. There's a "Voice Search" application in the App Drawer.
13. The "Market" is slightly different, with a separate tab for "Comments" once you select an Application.
14. You can pinch-zoom on the App Screen in TouchWiz to see thumbnail views of your installed Applications (by 'nishunb')
15. Creating Playlists is now easier! When you create a new Playlist in the Music Player....you can select multiple songs ala iPhone/iPod Touch style
(by 'adbaby89')
16. The soft-key "Back" button seems to have been disabled while playing Videos. Instead, a new "Back" option has been introduced in the top right corner to exit the video. Tap once on the screen to pull down this option (by 'adbaby89')
17. The 'YouTube' Application has been updated. You can now view Comments while watching Videos. (by 'abhinavj01')
18. A "Search Bar" has been added to the Contacts List. (by 'KBNN')
19. Flash works in the default Browser (by 'abhinavj01') [ Doh! How could I miss that! ]
20. Connecting in "Mass Storage" mode is now more User-Friendly. You don't have to pull down the Notification Bar to "Mount SD Card". Instead, a message is displayed on the screen that allows you to "Turn On" Mass Storage. (by 'abhinavj01')
21. To immediately 'mute' an incoming Call, you can press the "Power" Button once. You can't unmute it this way though. (by 'sebyyy' )
22. The "Logs" show all the logs including Calls as well as Messages, as opposed to Eclair. However, you can tap the "Menu" button and view specific logs, e.g. Dialled, Received, Messages, etc. (by 'SGSI')
23. When you switch the Phone off, it vibrates to indicate when its completely shut down. (by 'caesey')
24. You can uninstall Applications by dragging their Widgets from the Homescreen to the 'trash can' while removing them, and hold it there for a second. (by 'PinkMirrorKirby') [ I can do this on LauncherPro - couldn't earlier; but not on TouchWiz ]
25. Applications can be moved to the external SD Card as long as they support this feature.
26. GMail's interface has improved. You can now see colored labels, mini Toolbar within mails(star, reply, reply all, fwd), minor UI tweaks, and the overall experience is a lot snappier. (by 'caesey')
27. Groups made in gmail contacts are now visible on phone's contact groups list. These were not previously visible on eclair. (by 'Purnil')
28. With Android 2.2 USB storage mode works on a Mac 10.6 system without going to the Debug mode as you had to in 2.1 (by 'KingsleyM') [ I can't confirm this since I haven't got my Hands on a Macintosh, but we'll trust Kingsley! ]
29. According to a lot of Posts and from personal experience of monitoring(judiciously) for more than 2 Weeks, it can be confirmed that FroYo has reduced the Battery life of the Galaxy S.
==========================================================
Minor changes:
1. The AllShare application icon has changed
2. While switching the Phone on, the "S" that was displayed in plain milky White earlier once the flashing ends, now appears in 3D dirty White.
3. The number of options have increased when you press the 'Call' icon. Now there is a SMS shortcut at the bottom of Dialler screen (by 'nishunb')
4. "USB Settings" (Kies/Mass storage/...) has gone from:
'Settings->About phone' in Eclair to 'Settings ->Wireless and Network' in Froyo
(by 'SGSI')
5. Menu icons added when you enter the first screen of "Settings"
6. There is an "Auto-rotate" option in the notification bar, and the "Vibrate" option has been changed to "Silent".
7. After opening a conversation midway in the Messages list, tapping on "Back" takes you to the position of the previous position and not to the start of the list, unlike Eclair. (by 'abhinavj01')
8. The Applications have been re-arranged in an Alphabetical order in the TouchWiz App Drawer. (by 'abhinavj01')
9. A new 'Folders' Widget has been added to the TouchWiz Widget List. This was already provided by LauncherPro. (by 'abhinavj01')
10. A few more Wallpapers (Static and Live) (by 'abhinavj01')
11. Few Applications such as "Press Reader" have been added, but they haven't been enabled yet. (by 'ajincp')
12. Quadrant score increased marginally, both were run on stock ROM only (no lag fixes)
Eclair - 867
Froyo - 897 (by 'caesey')
13. The front facing Camera shortcut (Self-shot) is now directly available at the top left corner of the Camera interface (by 'KBNN')
14. The Notification Bar has thicker icons e.g. the Alarm Clock. (by 'Purnil')
15. The Gallery allows you to peek into Picture stacks using a pinch-to-zoom-out gesture. (by 'Purnil')
16. When you sneak at peek at the Screen while on a Call, you will notice the Notification Bar has turned Green in color. I'm not sure what use this is, but it's a change. (by 'sagarthaker')
--------------------------------------------------------------------------------------------
I'll keep adding to the list as we 'discover' more, and you could give me some points to add to the list as well! If a feature that was already present in Eclair (unrooted/not lagfixed) has been mentioned here as well, please let me know.
Hope this helps
I thought I'd make a list of the changes that FroYo(DDJP6) brings about, since I've noticed a few questions being asked about it and I couldn't find a thread related to it(maybe my Search terms were different
)So far, these are what I've noticed, and I will keep adding to them:
==========================================================
1. TouchWiz now has pinch-to-zoom
2. Swype has a 'move-cursor-to-edit' option. Click on text and you'll get a small indicator of the cursor's current position
3. You can take Screenshots. Hold the "Back" button for a second and then press the "Home" button.
4. When you push the "Power" key for a couple of seconds, you'll see an added option - "Data network mode", along with the previously existing "Power Off" mode.
5. USSD Codes (*111#, *123#, etc.) will now run without having to switch off the "Mobile Tracker", helps with viewing your available Credit Balance!
6. Swype's word-prediction has gone for a toss, although usage over a few days will get it back in shape, predicting the words you mostly use once again.
7. Browsing lenghty menus (e.g. message list, Contact list) is faster than before, as compared to the stock Eclair (unrooted, no lagfix). However the App Drawer seems to be a little jerky, but I think that might be because of my version of LauncherPro Plus (0.8.1.1)
8. New Widgets have been added (e.g. News & Weather, Dual Clock, Market, Home Screen Tips, etc.)
9. The "Task Manager" that comes pre-installed (at least it was in mine) now has a separate tab for "RAM Manager" which lets you clear memory at 2 Levels.
10. "Samsung Keypad" now has a "Voice-to-Text" input option available.
11. Skype works.
12. There's a "Voice Search" application in the App Drawer.
13. The "Market" is slightly different, with a separate tab for "Comments" once you select an Application.
14. You can pinch-zoom on the App Screen in TouchWiz to see thumbnail views of your installed Applications (by 'nishunb')
15. Creating Playlists is now easier! When you create a new Playlist in the Music Player....you can select multiple songs ala iPhone/iPod Touch style
(by 'adbaby89')16. The soft-key "Back" button seems to have been disabled while playing Videos. Instead, a new "Back" option has been introduced in the top right corner to exit the video. Tap once on the screen to pull down this option (by 'adbaby89')
17. The 'YouTube' Application has been updated. You can now view Comments while watching Videos. (by 'abhinavj01')
18. A "Search Bar" has been added to the Contacts List. (by 'KBNN')
19. Flash works in the default Browser (by 'abhinavj01') [ Doh! How could I miss that!
]20. Connecting in "Mass Storage" mode is now more User-Friendly. You don't have to pull down the Notification Bar to "Mount SD Card". Instead, a message is displayed on the screen that allows you to "Turn On" Mass Storage. (by 'abhinavj01')
21. To immediately 'mute' an incoming Call, you can press the "Power" Button once. You can't unmute it this way though. (by 'sebyyy' )
22. The "Logs" show all the logs including Calls as well as Messages, as opposed to Eclair. However, you can tap the "Menu" button and view specific logs, e.g. Dialled, Received, Messages, etc. (by 'SGSI')
23. When you switch the Phone off, it vibrates to indicate when its completely shut down. (by 'caesey')
24. You can uninstall Applications by dragging their Widgets from the Homescreen to the 'trash can' while removing them, and hold it there for a second. (by 'PinkMirrorKirby') [ I can do this on LauncherPro - couldn't earlier; but not on TouchWiz ]
25. Applications can be moved to the external SD Card as long as they support this feature.
26. GMail's interface has improved. You can now see colored labels, mini Toolbar within mails(star, reply, reply all, fwd), minor UI tweaks, and the overall experience is a lot snappier. (by 'caesey')
27. Groups made in gmail contacts are now visible on phone's contact groups list. These were not previously visible on eclair. (by 'Purnil')
28. With Android 2.2 USB storage mode works on a Mac 10.6 system without going to the Debug mode as you had to in 2.1 (by 'KingsleyM') [ I can't confirm this since I haven't got my Hands on a Macintosh, but we'll trust Kingsley!
]29. According to a lot of Posts and from personal experience of monitoring(judiciously) for more than 2 Weeks, it can be confirmed that FroYo has reduced the Battery life of the Galaxy S.
==========================================================
Minor changes:
1. The AllShare application icon has changed
2. While switching the Phone on, the "S" that was displayed in plain milky White earlier once the flashing ends, now appears in 3D dirty White.
3. The number of options have increased when you press the 'Call' icon. Now there is a SMS shortcut at the bottom of Dialler screen (by 'nishunb')
4. "USB Settings" (Kies/Mass storage/...) has gone from:
'Settings->About phone' in Eclair to 'Settings ->Wireless and Network' in Froyo
(by 'SGSI')
5. Menu icons added when you enter the first screen of "Settings"
6. There is an "Auto-rotate" option in the notification bar, and the "Vibrate" option has been changed to "Silent".
7. After opening a conversation midway in the Messages list, tapping on "Back" takes you to the position of the previous position and not to the start of the list, unlike Eclair. (by 'abhinavj01')
8. The Applications have been re-arranged in an Alphabetical order in the TouchWiz App Drawer. (by 'abhinavj01')
9. A new 'Folders' Widget has been added to the TouchWiz Widget List. This was already provided by LauncherPro. (by 'abhinavj01')
10. A few more Wallpapers (Static and Live) (by 'abhinavj01')
11. Few Applications such as "Press Reader" have been added, but they haven't been enabled yet. (by 'ajincp')
12. Quadrant score increased marginally, both were run on stock ROM only (no lag fixes)
Eclair - 867
Froyo - 897 (by 'caesey')
13. The front facing Camera shortcut (Self-shot) is now directly available at the top left corner of the Camera interface (by 'KBNN')
14. The Notification Bar has thicker icons e.g. the Alarm Clock. (by 'Purnil')
15. The Gallery allows you to peek into Picture stacks using a pinch-to-zoom-out gesture. (by 'Purnil')
16. When you sneak at peek at the Screen while on a Call, you will notice the Notification Bar has turned Green in color. I'm not sure what use this is, but it's a change. (by 'sagarthaker')
--------------------------------------------------------------------------------------------
I'll keep adding to the list as we 'discover' more, and you could give me some points to add to the list as well! If a feature that was already present in Eclair (unrooted/not lagfixed) has been mentioned here as well, please let me know.
Hope this helps
