I've been following the discussion about Real ID for a few weeks now and mostly found myself agreeing with the skeptics whenever the subject came up, whether it was because of the occasional urge to play on your own or due to serious privacy concerns. (I was going to link to a post on the subject at Murloc Parliament here, but the site seems to be down for the time being. Oh well.)
Now the patch finally reached Europe and I have to admit... when I logged on and found a guildie whom I know and trust online, I immediately whispered her asking whether she wanted to be my Real ID friend. She was happy to oblige and we then played a bit of "now you see me, now you... still do" with me hopping back and forth between various alts. There still seem to be some bugs though, as the realm and zone fields were always blank, so you couldn't actually tell when you were talking to a character on a different realm. My customised (with the default interface) chat windows also got messed up so badly by the chat change that I had to reset them completely, but it didn't take long to get things back to the way I wanted them to look.
A bit later I asked another friend whom I've known for years to exchange Real IDs as well, but she declined saying that she was using a super secret e-mail adress for her WoW account that she didn't want anyone else to know. I didn't take offense. The old, "normal" friends list for WoW only still works fine so it's not as if I'm losing anything by someone not accepting my Real ID request.
Don't get me wrong, I still agree that the Real ID privacy options are very poor (though you can't actually see the online status of friends of friends as I had feared) and could do with some more choices. But if everyone involved is aware of how much information they are giving out and fine with it, it's a fantastic way of staying in contact with people who have a lot of alts, especially if you have a lot of alts too. (If you don't have some sort of shared friends list addon, remembering to add all your friends' alts to your friends list on all of your alts is quite a hassle, not to mention that it can eat up a lot of your limited friend slots.) I've only just started cleaning up my friends lists (removing all the individual alts of people who I now have as Real ID friends anyway), and it's rather liberating.
I can't guarantee that I won't have regrets later on if I ever feel like "hiding" on a new alt and find myself unable to, but then again, I'm only adding people whom I trust a lot anyway; what's the worst that could happen?
Friend: Oh hey, is that a new alt?
Me: Yeah, I felt like doing the human starter area again and wanted to get away from the guild for a bit.
Friend: Ah, I guess you wouldn't be interested in coming to ICC then?
Me: Not really, sorry.
And they'd understand, because they are my friends.
Meanwhile Back in the Garrison
10 hours ago