I generally don't play online. Most of the games I own are single-player only. Since I'm the only one of my gaming friends who has a PS3, and the considerable lack of local multiplayer in video games these days, I don't play games with my friends very often, online or otherwise. We generally resort to combining our strengths to play a single game. It's how I beat the Tower Knight in Demon's Souls.
For the most part, I play online in games where the single-player and the online are seamless. (e.g. Dark Souls, Journey)
I have gotten into Together Mode on Kid Icarus: Uprising, though. That's pretty fun, and helps it me out in the single-player mode, so I have an incentive to play.