Zenith pretty much nailed it.
One of the big reasons that clans were removed is because the majority of them served no purpose. I wish Zenith hadn't changed the name because it would have served as a great example, but up until yesterday, the MLP discussion thread was called the "MLP Not-Clan" because we didn't want the formalities that the clan forum brought (clan "leaders", hierarchies, signing up, YOU'RE NOT IN THE CLAN YOU CAN'T POST HERE MODS HELP HELP). All we wanted was a thread for fans of MLP to chat. No signing up. No "clan rules." Just pop in, say something like "hey this show's cool I've watched X episodes, my favorite pony is X" and be on your way.
The thread existed outside of the clans forum for that very purpose. That thread isn't the reason why the clans forum was removed, but it's a very good example of just how useless it was. If it wasn't one of the over nine thousand TCG "teams" plaguing that forum, it was of some topic that would could be discussed just as well in this forum (sports, Sonic, writing, school, anything).
The only difference is now anyone can just jump in and post whenever they want - no need for frivolous formalities.
scuba steveE, I won't claim that your points aren't valid, but bringing back an entire forum just for a couple of tcg/vg "teams" just isn't gonna happen. Part of the reason that the Pokebeach Team White and Team Black are being disbanded is because most of the activity is being done in Team White. That one specific section of the forum flourishes, and any TCG players not part of that team suffer for it.
Is that a bit clearer?