Quote:

Registration API promo tool Registration API 11-10-2011 New promo tool Now is possible to allow your visitors to create an Xlovecam account directly from your website pages. Check out our new promo tool - Registration API - we provide an example script for it but is possible to create your own in other programming languages or you could simply customize our script. Registration API can be found under your ACWM account » Promo Tools » Xlovecam » Registration API

The term API is APplication Interface?

The FB and Twitter log-in buttons you see are one example -- those APIs also track data for the website whether you log in (are logged in (or not?))