Bill Gates quits Facebook, citing too many friends

You can read about it here. IMO someone like Bill Gates doesn't really need Facebook as a personal tool, so if that's all he was using it for then it makes sense to quit. For the promotion of a cause though Facebook and Twitter are extremely useful, and even moreso if the cause happens to be global. Bill Gates does have his own causes to promote, though when you're a person whose mere resignation from a site makes the news it's probably more worth it to simply make a press statement and watch people write about it for you, both on the news and on sites like Facebook and Twitter. See:

So he doesn't really have to do any promotion online himself.

It would be interesting to see an algorithm comparing one's social/media status with the effectiveness of using an online platform to promote one's own cause. At the very bottom rung you would have people with no sway in the media whatsoever and complete anonymity, who have no way to promote their cause without online tools, and at the top are people like Bill Gates who are better off using their time for other causes as their actions themselves make more news than if they were to do something online themselves. It's kind of like the saying back in the 90s that if Bill Gates were to drop a $500 dollar bill it wouldn't be worth his time to pick it up.

For politicians this is naturally quite different as they need to continue to maintain support from the people they represent, so it's a constant battle with entropy for them. Plus, as a politician you always have the opposition trying to misrepresent things you might or might not have said, and any letting up lets them frame the situation in their own words, and you don't want that.