Google could also use a number of mechanisims to get email recipiants to connect to the Gmail service though the browser, including keeping email attachments server side inserting an URI in the email. Hotmail, or any other web email provides could do the same, even using the spammer trick of webbug images emmbedded in the HTML'ed email. Significant profilable information can be gathered from the email headers alone.

There is a potential network effect on the erosion of privacy, made more prominent with users moving to a few very large service providers.

Privacy advocates have a legitmate concern over the issues surrounding the profiling and privacy of email. While Google remains under its current management, I am personally less concerned. However just as in January 1998 Hotmail was purchased by another company, Microsoft, Google could be sold to another company with even less moral scruples.