μTorrent recently added a $4.95 annual subscription to make the popular BitTorrent client ad-free.
The ad-free option had been part of ?Torrent Pro, but that subscription costs $19.95/year and includes a lot of (at least to me) superfluous features like virus filtering and multimedia conversion.
But $4.95 just to remove ads is more in-line with the mobile model where an app comes in a free, ad-supported version and a pro version that costs from $2.99 to $4.95.
Subscribing was a no-brainer to me given how much I use μTorrent.