People use it - but the name of the software is Fusion - Clickteam is the name of the company that writes Fusion. The free version is more of an introduction or stepping stone into the paid versions, so mostly you'll see games written with the paid versions, and if you use Fusion Developer, like I do, then of course there's no brand inside my games to indicate that, but they should be listed under the link that No Time To Play posted, because I fill in those fields when I publish something here.