Flirting is like a double-edged sword for me.
It happens a lot online because it's so easy to approach people, not that I have much of a better time doing it online than offline. I'm too used to people appraoching me first, heh.
Anyway, I find flirting to be a great way to be flattered and to flatter someone else. However, sometimes it's just simply fun. Of course, one person might be serious while the other person is just doing it for fun, then you have a potential problem. It's pretty difficult all around in some cases. ;| Offline I only flirt with someone after they give off some sort of hint of being interested in flirting, hahah. Then again, I'm pretty shy so I probably lose out on a lot of great opportunities. Like I said before though, flirting online is a lot easier.