Thanks for your thoughts. I’m not sure about the title of this post – the plugin is not invasive – feel free to check AddToAny’s privacy policy and/or explore the source.
The reason most service URI schemes are redirected through AddToAny’s servers is so that visitors are always properly connected to each service; no plugin updates ever required.
I’m sure you’ve stumbled across blogs, etc. that have sharing/bookmarking service dead-links, or links to totally defunct services (i.e. an outdated Sociable plugin). These links are not useful and a little embarrassing, so we took on the responsibility in early 2006 to help resolve the problem. Working with each of these services to provide a standard and reliable link exchange service, we’ve gotten to where we are today, which is pretty exciting. ??
Other reasons for links passing through AddToAny: automatic URL shortening, prompting users to enter their WordPress blog URL, OAuth. Respectively, for example, we do URL shortening for Twitter, prompt for the “Press This” URL for sharing to a WordPress blog, and do the OAuth handshake for other services.