Are there enough people playing old games online? (Excuse me for being ignorant, but that is why I am asking: Educate me!). I mean, I don't know much about online gaming and I may get the PS3 almost exclusively to play online. How many years do you think we may have support for the console in terms of games and servers?

Obviously it's a great time to buy a PS3 but I think you should wait 2 months for the inevitable price drop in Aug/Sep, possibly with an even slimmer PS3.

That's a great question and I wish we knew more.

From my experience, Assassin's Creed Brotherhood has up to a few hundred players playing online at the same time, Crysis 2 (from Spring 2011) has perhaps a couple hundred players online at any time.  Two Worlds 2 (niche RPG from late 2010) has around 10-20 guys playing at any given time. Dante's Inferno (2010) usually has none.
(it seems that PSN online gaming is divided into regions since I meet players from all over the world but seldom from the USA).

Servers will probably be kept online for a long time (many years) but my problem is that there simply are not enough players in the PSN echo system to support smaller and older games.

When you start buying a few games for the PS3, you're actually opening a flood gate.

Currently, you have 6 years of support you missed out on.  It's time to play catch up.

servers depend a lot on the Publisher - EA for example is known for shutting down servers for a game after 2-3 years, but Sony's own games (if your are most interested in exclusive) enjoy a really long online support. I still play Hot Shots Golf 5 online from time to time and that game is 5 years old.

Yes.

Yeah, I would recommend a PS3, but probably after a couple of months when it gets another price cut.

I got my PS3 only a year ago, and I'm loving it a ton! I'm so glad I got it. Now would be a great time to buy, because the console is a pretty good price, and you can get tons of great games from 2006-2010 at low prices, if you buy used. You can get pretty good deals on new games as well

I don't buy any console for one game.

If all the games you want are basically 3rd party, then just wait for WiiU.

If you want quite a few first party PS3 games, then wait a month to verify if there will be a price cut on PS3. (I really think there will be soon)

OR just buy one of the used PS3s on craigslist or Ebay. Tons of savings there too.

Again, I'd only buy a console if there were four or so games I wanted to play and they were only on that console.

Its the perfect time to get a PS3 you are going to find brand new games you haven't played at 30$ or 15$ bucks.