The Vanilla Forums PHP SDK by Vanilla Forums integrates discussion modes into online communities. Individual add-ons include language as plugins, templates as themes, and scripts as open source tools. Additional information to customize and integrate forums with cloud solutions available at https://github.com/vanilla/vanilla
Stack Overflow, the very successful question and answer site for programmers, have now released their own API into public beta. The API actually works with all of the Stack Exchange sites, including serverfault.com and superuser.com, with more sites possibly launching in the future. The API is supported by the site http://stackapps.com.
Sustaining an effective engagement campaign can take a surprising amount of work. You could limit yourself to following the leads from the data you collect, but following without interacting first will get you a very low follow-back ratio. More importantly, if you follow and then forget people, they may follow back, but they’ll soon forget you. A high number of followers who don’t reply to, mention or retweet your account are of no value. True engagement is long-term and repetitive.