Frasch spotted this (during a techie interchange on how rubbish Windows XP is at searching for and through files). It basically shows just how useful the new Google Desktop is at finding, indexing and reading on-line email such as Yahoo! regardless of who owns the mail account!
Online wiki-mail anyone?!
Addendum :- Frasch also sent a couple of links, here and here, both found using Goole, which is kinda comforting!