We launched Applozic (applozic.com) 'Chat & Messaging As a Service' for developers on product hunt. Results were good, we got some traction and feedback from there.
producthunt.com/posts/applozic
Best response we got is from Android Arsenal, if you have something for android developers, post it on Android Arsenal. For the first week, on an average we got around 40 signups. We are still getting 2-3 signups weekly from the site.