Kyle, gmail is not open to the public yet so the accounts are valuable to some people (for example, if you wanted [email protected], you'd probably want to get an account pretty soon to make sure it wasn't claimed by someone else). See http://www.gmailswap.com. Yes, it's not a domain name, but there's only one email address [email protected] and I have it.
Herm, it's a policy not a law. And I haven't violated anything by just asking "what's it worth."
Chris, it's better than inappropriate ads. The text ads on Gmail are much less annoying than the banner ads that are on almost every other website on the Internet. This is one of the reasons why people love Google also.
Unless you use some sort of email encryption, like PGP, or can ensure that the entire path that the email travels from one site to another is encrypted (you'd probably have to control the entire network for this to happen), you should treat email about the same as you treat a postcard or an inner office memo. It's quite easy to read someone else's email if you want to, even without their password or access to their computer.
Gmail is a cool service. I think it's a great new business model, and I hope Google decides to turn it into a mainstream offering. The amount of community support for a product that hasn't even been released is amazing.
None. It's not reading the e-mail, it's matching keywords to words that an advertiser specifies as appropriate for their ads. It has no context, it's not keeping a database of what you like and don't like. It's not Amazon.
To answer Grant's question: Not more than $1, I'd bet. And even then you can't sell it, so why does it matter what it's worth?
Google can toss words and contract conceptions around, but unless I'm mistaken, most of the times a EULA has been challenged in court, it's fallen, usually because what constitutes to "agreeing" to it isn't strong enough to be considered legally binding (clicking a button underneath a license nobody reads, or breaking a seal on a software envelope).