A lot of companies have adopted apps such as UserVoice(<a href="http://uservoice.com/" rel="nofollow">http://uservoice.com/</a>) for different purposes.<p>If you want to investigate the idea of using it for your own company, people have already built services that hosted reddit/hn clones.
<a href="http://slinkset.com/" rel="nofollow">http://slinkset.com/</a><p>and if you need more meat, reddit is opensource