One particularly interesting way of promoting your open source project is StackOverflow's own Free Vote-Based Advertising for Open Source Projects1:
Here’s how it works:
- Visit the special meta.stackoverflow.com question thread for this advertising period. It will always be tagged [open-source-advertising].
- Construct a 220×220 image advertisement for the open source project that you would like to publicize to your fellow programmers.
- Post an answer containing your image to the question. It must be in exactly the right format, as documented in the question itself.
- Get at least (n) upvotes for your answer.
- Your advertisement will now be featured in Stack Overflow’s remnant ad inventory, in the sidebar ad slot on most pages.
I think it will serve the an eye specifically towards finding other developers interested in contributing goal finely, as the most visited sites of the network are geared towards developers (SO and this one) or technical savvy people (SuperUser).
I'm also very fond of Ohloh:
Ohloh is a new kind of software directory, combining community-driven content with a unique source code crawler that monitors up-to-date development activity.
Lastly, if your project relies on other open source projects, you could reach out to their communities.
And of course my answer is meant in addition to everything in Chiron's answer.
1 Also: Free Vote-Based Advertising for Open Source Projects and Open Source Advertising - Sidebar - 1H 2012 on Meta StackOverflow.
