Recommendation / Marrying Up Algorithm in PHP?
<p>Is there something that has been already developed and is Open Sourced?</p>

<p>I'd like to develop a site that is like:</p>

<p><a href="http://www.swap.com/" rel="nofollow">http://www.swap.com/</a></p>

<p>What I envisage is that a USER A puts in what they have, dvd's, book's, cd's, etc.  </p>

<p>USER A then puts in what they are looking for themselves.</p>

<p>The system then does a check against all the users.  It finds that USER B is requesting items thats in USER A's inventory.</p>

<p>So USER A can swap item X for USER B item X.</p>

<p>I just don't want to try (operative word here being try) to reinvent the wheel if its kinda been done before.</p>

<p>Thanks</p>
