Here is some more info off the site about what Impulse offers to developers. Looks like a good deal to me but of course they do take a cut.
Put your game, application, utility or any other type of PC software on Impulse and reach millions of users around the world. Impulse is a digital distribution platform that enables your users to associate your program with their account and easily access the latest/greatest version of it. Increase your sales, reduce your support costs and take advantage of the features of the fastest growing digital distribution platform on the PC.
Impulse allows developers to:
1.Distribute their software to millions of users with very little effort
2.Receive 70% of the gross revenue on each sale (85% in the event that the sale is made from the developer's website – better than most ecommerce solutions)
3.Make use of Impulse::Reactor, an advanced and free development platform that offers a wide range of features from intellectual property protection to multiplayer matchmaking.
See the documents below for more information on the features of Impulse