I'm posting this here because I assume it will require AJAX to accomplish.
There are social networking sites such as Facebook which, when you sign up, they access your gmail or yahoo etc email account to check if any address in your address book match with any of the members on the site.
I am setting up a site with osdate and would like to add this capability. I have no idea where to start on this but I'm hoping there is some script out there that can help with this (an osdate plugin would be perfect, but I'm not above configuring something else to work with osdate).
Please, if you have any idea where to start on this, please let me know.
Basically, you'd have to contact gmail and yahoo and cut a deal with them to use some API, of theirs, which will allow your server-side code to query them for a list of email addresses. AJAX is generally not suited to this task because AJAX is generally not allowed (for security reasons) to access cross-domain resources.