and Twitter

Probably no reason.

Or they're doing it for the fans? The clearly professionally managed online presence that suddenly appears exactly 10 years after the mega-group called it quits.

"The fans will love it" they might have thought to themselves. "We'll throw in a few $k to maintain our on-point online presence for that reason."

Or is it possible this is being done to re-establish the brand online – to make a future marketing campaign go down smoother?

We don't actually know. This post is only so if they, say – announce a tour, we could point to this post and say "we called it".