It's fun. It's a whole lot of fun, in fact. Mind you, I've never released any (I did release a metamorphic code engine for .NET some years ago, but that's the closest I've come), but it's really fun to think through it and come up with clever ideas. It also helps you gain perspective for the security side of things.
Its a way of having your work everywhere, imagine being able to know that millions of people have your work on there computer, and seeing it read and blogged about, i guess its exciting.
