OK, well, bumping this because it's a top web result for "android swap partition" now.
It's nice and all that Android *tries* to conserve/free memory as needed (like a 5-year-old "tries" to go to bed). In reality, it fails miserably and it's resulted in my phone nearly getting snapped in half many times out of frustration with low-memory problems. I've got a Nexus S 4G - and I know this isn't the forum for that - that has <512mb RAM. For some reason it *NEVER* has any free memory available - nor cached memory. All consumed by background apps and services I *do not want* running - but can't stop. System crap, like the Home launcher, which I don't want to completely exit and have it tediously re-initialize every time I hit "Home" (when I hit home, I want it back to the launcher in under one second - not TEN!). The "NFC service" which I can't exit. About 60mb of Bluetooth daemons. All kinds of idle crap that has resources being consumed by static resources that could be swapped out to a swap file/partition and have the relevant parts loaded on demand.
I've dug deep into the developer tools with this phone and found no way to free memory. All components consume over 20MB of RAM each, due to bloat in the Android OS since that article was written in 2009. Today, I believe it could greatly benefit the OS to have swap available, because the OS has grown far beyond its means and it's now crippling once-useful devices with runaway garbage. I can't even stand to use my phone for more than one thing anymore: music in the car (Spotify) and navigation/GPS logging (Waze) simultaneously. Spotify skips because the phone keeps cycling background task-kills that often includes Spotify itself. I damn near go road-rage out of control when Spotify gets task-killed with Waze in the foreground - and that's ALL I opened!
Seriously. That article is from 2009. We need swap now.