This app was mentioned in 3 comments, with an average of 4.67 upvotes
lol... I actually didn't even know about http://www.mobilestrikeapp.com/
I see it's got a 4.1 stars on Google:
https://play.google.com/store/apps/details?id=com.epicwaronline.ms&hl=en
And 4 stars on iTunes:
https://itunes.apple.com/app/mobile-strike/id934596429?mt=8
But it would be difficult to try to find a famous person who has not promoted at least one mobile app or online service (whether their own or someone else's), and most of them do that from their Twitter feed, which of course they want everyone and anyone to follow, and that could of course be counted in itself. These are the top 1,000: http://twitaholic.com/
Eminem actually has 2 apps: