EepURL is MailChimp's in-house URL converter. EepURL generates shortened links to replace longer, more complex URLs. It's similar to tinyurl, but with behind the scenes tracking capabilities; so it's more like bit.ly, but created for MailChimp specifically.
With EepURL, we've made it even easier for you and your subscribers to share your campaigns. When you auto-post your campaign to Facebook or auto-tweet it to Twitter, we're sharing a shortened EepURL instead of a long campaign archive link. It's also built right into our Archive Bar for fast and simple sharing on social networks like Facebook, Twitter, and Google+. You can even share to your own website or blog using the Copy button.
Using EepURL's built-in tracking features, you can see where in the world people are reading your campaigns, and view the top 10 sources generating traffic to your shortened EepURL archive link.
Other MailChimp applications use and depend on EepURL's shortening features, so its domain reputation is kept under close guard. It's not available for public use outside of MailChimp.