[Father]

This was also a much used trick: http://news.ycombinator.com@1249739877 Although most browsers have implemented a warning of some sort it can still hoax spam-filters that use a regexp pattern which doesn't account for this type of behaviour.

[gizmo686]

Could you explain the link?

[mkl]

I'm not sure about the "news.ycombinator.com@" bit, but the number can be identified like this:

  $ ping 1249739877 
  PING 1249739877 (74.125.132.101) 56(84) bytes of data.
  64 bytes from 74.125.132.101: icmp_req=1 ttl=41 time=395 ms
  ...

Looks like a Google IP.

  $ nslookup 74.125.132.101
  Server:         127.0.0.1
  Address:        127.0.0.1#53
  
  Non-authoritative answer:
  101.132.125.74.in-addr.arpa     name = wb-in-f101.1e100.net.
  ...

Sure is. And Google redirects wb-in-f101.1e100.net to its main page.

[recoiledsnake]

The part before the @ part is supposed to be the username for HTTP authentication. The complete format is http://username:[e-mail] but the password is optional.