I recently put up a project, called Hebel, that I've been working on to GitHub. It's a framework for GPU accelerated deep learning written in Python and Nvidia CUDA. I posted about it on Google+ and soon afterwards it was picked up on Hacker News and went slightly viral for a few days. I later posted about it again in the Machine Learning subreddit as well and altogether my project picked up 822 stars and 47 forks on GitHub, which was really exhilarating. 822 stars means my project is in the top 200 Python projects on GitHub and in fact has more stars than some high profile and widely used Python projects like virtualenv.
Despite the considerable interest for my project, I'm very disappointed with the actual engagement I have seen so far. None of the 47 forks of my projects have ever had any commits, I haven't received any pull requests, and only three issues submitted were submitted by two people. It seems that my project is potentially very interesting to many people, but they only star or fork it once and then never return to it again or use it on a continuous basis.
How can I improve engagement in order to have users either submit bugs or enhancement requests or have contributors submit changes?