@scribu opened a core trac ticket here for Proper Network Activation problem in multisite. It seems like its fixed in wp 3.1.
But scribu was saying it doesn’t fixed in wp 3.1.
So he released a plugin for proper network activation.
I’m using wordpress multisite. So can anyone tell me whether this problem fixed in wp3.3.1 or not?
In short: No, it hasn’t been fixed – You should use the plugin instead.
In Detail: Activation hooks should work for the main site properly. For subsites (or as Nacin pointed out: for all sites), you should use a proper upgrade routine. Not that I double that 1).
1) Note to myself: When a core dev says that core internals are lame, then this should tell me something. Not shure what exactly, but I’ll think about it.