Pseudonymous rather than anonymous, generally. And it can work better than you'd think, depending on how you've met! One interesting facet of how internet relationships are formed is that certain phases of those friendships might happen in different orders than they might in the physical realm- for example, on a rule-less gameserver that I used to play on (think literally 4chan in game form with a very old persistent map), the users would tend to go through trust first, and then getting to know each other later. This is efficient due to the lack of consequences you deal with for most things online, since if someone breaks that trust you will just find ones who won't. In the case of that particular gameserver, I've seen groups of like a dozen people capable of sharing even their account credentials to various things without having much fear, and this kind of thing really speaks volumes IMO.

A number of people I've met in this way (chatrooms, games, etc) I've actually come to work on real projects together with. Though at this point, considering how comfortable we are giving info about ourselves, I suppose the pseudonymity somewhat lifts itself away over time.