On profile pages, there used to be an “Activity” tab. People could essentially post messages on your wall. It was hardly ever used and looked like a big mess. It was also home to a crapload of spam (pretty much everybody had spam on theirs). That was a crappy experience when clicking on someone’s profile.
I removed that tab and I think it’s much better.
Plus, Google will see a ton less spam links now, which I think is extra important with their last update.