1.KGS:http://www.gokgs.com/

2.NSG:http://nostrive.appspot.com/

In the past, I often play in KGS,
recently, I play in NSG more and more.
In NSG, I can play mang go games in the same time.

NSG looks interesting, but the translation needs more work (ex: losters / losers, but replacing the complete header would be better)

I'm also slightly amused to see that they didn't do the hard things (ranking, time handling, ...) but they put that fact as an advantage

It's quite similar to OWGS, except it looks like a few are playing on NGS.

Oh, and komi is fixed, no handicap it seems, no game list (invite player only), no nigri (the inviter is black).
Could be great, but feels unfinished right now.