A Reciprocal link is where two web sites make an arrangement to link to each other. Typically this is done personally through email with webmasters you know.
At some point people figured out to automate this somewhat and that is exactly what Beacon Hill's Reciprocal program is.
You can use a simple form to add your site's information and where you've placed a link back to Beacon Hill. With this, Reciprocal will check your reciprocal link for a valid link and build a page with your sites link nightly.
The application is downloadable and includes the full source code for inspection and customization. A pre-built runnable application is included in the download so the application can be tried without having to rebuild.
Those users interested in building Reciprocal should be familiar with Ant and Java.
To download:
http://www.beaconhill.com/
