What follows started off as a reply to a PM from richkoi. You see, I went off topic over here and richkoi PM'd me (very nicely) to ask what I meant.
Then I set off to jot a couple of sentance in reply and ended up ranting. I have read several GMail rants lately, here's mine:
Thanks for the PM, let me say that what I know about Gmail is from what I've read and heard. I don't have a Gmail account and don't know anyone personally who does.
Well, I realize that ISP's and webhosts have to scan mail to some degree in order to provide their services, so I know that email privacy is limited to some extent anyway.
But, google scans every email and archives it to make it searchable. Think about an extreme case of someone whose email privacy is especially important (I admit they are extreme cases, but it could happen on lesser degrees too): a Cuban man emailing relatives in the US, someone unhappy with the government (whichever), someone trading mp3's online, someone cheating on their wife, etc., etc. Many of these emails will end up on Gmail's datacenters.
“But they are scanned and read by machines, not humans”. Do you think the fact that they are categorized, indexed, and painstakingly organized by machines is a good thing? The fact is that with google’s search technology, someone COULD find the email where you told your friend that you like to dress up in women’s clothes that much faster and easier.
Any such extensive (imagine 1 billion gmail subscribers with 1 gig of storage each) storage of emails will be a target for abuse. A google employee who has access to the email database finds naked pictures of some political candidate and posts them on the web. Hackers look for emails where grandma emailed her credit card number because she doesn't know any better. Chinese government officials bribe a google employee to look for information about political dissidents. The FBI gets a search warrant to check google's data center looking for kiddie porn, but stumble across your email telling your buddy how you cheat on your taxes.
Think about all the ISP's who were court ordered to release personal information so the recording industry could prosecute mp3 traders.
Not to mention, the common screw up: a bug occurs where for only 15 minutes every Gmail user can search everyone else’s email.
I'm not a very creative person; imagine what someone with a lot of talent and some time on their hands can come up with. I'm certain there are a million different scenarios where this HUGE treasure chest of personal information could be made available to one person or another.
"If you don't want your email kept in Gmails database, don't get an account". I can't email someone with a Gmail account either. "Then don't email Gmail addresses". People forward emails all the time, even by avoiding Gmail completely at least SOME of my email will end up in a Gmail inbox. I email clients all the time, perhaps you can afford to turn away clients with gmail addresses; I can't. If (when) Gmail takes off like mad you can put an "I don't exchange email with Gmail users" message at the top of your checkout or “Contact Us” page if you want, and then just go ahead and do a 301 redirect to my site for Gmail users.
Sure, ISP's and webhosts are targets for all of the above. But each one is on a minute scale compared to Gmail. Not as attractive to abusers, not as many potentially abused in any one place.
Even if none of the above were remotely possible (if you think any of the above is impossible you’re kidding yourself) google has still done a horrible job of educating the public, online retailers, and online service providers about their new product. I don’t watch much TV, but I get my news online from several different sources, I listen to the radio, I read the newspaper, and I read industry magazines. I haven’t heard the first thing to put me at ease about my concerns. At the very least they should sack their PR (not PageRank) guy.
While I feel that all the arguments above are valid to one extent or another, I have to admit, the truth is simply this: I communicate with clients (retail, webservice, and day job) by email. I do not want an email I send them about their order, their website, their new facility, whatever, to trigger an ad from one of my competitors. Right as I am about to close a deal, the Gmail user looks in the right column at the highly targeted ads and sees an (apparently) similar item or service for a lower cost and chooses to go elsewhere. I don’t want my newsletters I work so hard on (heaven forbid I ever find some advertisers to pay me to list their ad in my newsletter) to trigger an ad for a competitor. My work is copyrighted, in this example my competitor and google ($0.23 per click, baby!) profited on my work WITHOUT MY PERMISSION. That’s the REAL reason I don’t like the idea of gmail.
Drive home safely, don't forget to tip your waitresses.