That sounds like a really cool idea. Have you submitted it here? Got me thinking of pluses and minuses, and ways to bootstrap. Probably somebody would have to put up a free email service that implemented these hidden auto-replies, and maybe submit some pull requests to open-source projects to use it. Maybe Android and iPhone apps for the service that handled the phone info side. Sounds a bit big for an individual side project to me, but maybe it's a startup. It would probably help to get input from a bunch of people/projects on what they'd want for specific use cases.
ufmace: I think writing a browser extension that configures filters + auto-responders on some popular webmails (Gmail, Hotmail, etc) would work best to entice users to adopt the technology. As I explained, many webmails already have all the necessary features to implement the concept (see FAQ 1 at http://blog.zorinaq.com/?e=76). Also, writing a smartphone app to do the same for mobile users would help. There is really no need to launch and run a full-blown webmail service.
I upvoted it, though I feel the pain on getting upvotes and reads on here. I think the last article I wrote got more upvotes on Lobsters than here. You gotta get just the right title at the right time, or it slides off the front page before anybody sees it.
I'm not sure what the best way to get going is. A webmail service dedicated to it would get the best UI, but there's the overhead of getting a webmail service with competitive features to Gmail, Yahoo, etc going and keeping it running. Or you could do a plugin or something, where it might be a challenge to put together a good UI and keep it in sync with Gmail's updates.
