Jajah will be officially announcing their click-to-call buttons on Monday. The buttons, which let people call the owner for free and anonymously, have been quietly in private beta over the past year. They are also taking on international calling card services and Jaxtr and Jangl, who already have click-to-call offerings on social networks and dating sites.
The call buttons are available to registered Jajah users and come as a bit of embed code you can put on your web page or at the end of an email. They come with several customizations. You can adjust the CSS styling, adjust the number it calls, and restrict which countries can try to call you.
When users click the button, the caller enters their phone number and Jajah connects the two parties over a VOIP line. The callee is then told who called and asked if they want to accept the call, say they're busy, or blacklist the number. If they accept the call, the minutes are charged to their Jajah account, like an "800 number". At two to three cents per minute, it can be used for some cheap long distance calling. For the cost conscious, Jaxtr and Jangl are still free, however.