There are problems with Gmail, of course. Im one of 31 privacy advocates and civil liberties organizations to have signed an open letter calling upon Google to suspend Gmail until the services privacy issues are properly addressed. One concern raised in the letter is that Google scans all incoming e-mail for the purpose of displaying targeted advertisements. I think that the growing trend toward putting ads in application software is troublesome, no matter whether the applications are running on my computer or on a remote server. Right now the only way Google makes money on Gmail is by having people click on those ads, but I fully expect a subscription-based version of Gmail to be available within a year that allows me to make those ads go away by paying a monthly fee.

A bigger problem with Gmail is the companys data management and retention policy. I like to think that I own the e-mail that I receive, but with Gmail Im definitely sharing that ownership with Google. If I decide to cancel my account, there's no obvious way to download all of my mail thats stored on Gmail. One of my annual housecleaning chores is to make a CD-ROM with all of the past years e-mail, but Google does not provide the tools that would let me do that, short downloading each Web page to a separate file. (Apparently, however, independent developers are filling the void that Google has left; click here, for example.) Unfortunately, use of such software appears to violate the Gmail terms-of-service agreement, which forbids the user from using "any robot, spider, other automated device, or manual process to monitor or copy any content from the [Gmail] Service." What's more, even if I terminate my Gmail account, Google essentially reserves the right to keep my stored email forever. (Here's the complete privacy policy.) Clearly, with possession of data comes control over that data.

Theres also concern that Gmail might become a one-stop shopping service for law enforcement, much in the way that America Online has become. Having a gigabyte of stored e-mail makes Gmail an attractive target: its not just a window into your present activities, but into your past as well. Just imagine the potential in a divorce proceeding!

Like any other Web-based application, Gmail doesnt work if youre not connected to the Internet. Now, e-mail might seem like an inherently network-based application, but I frequently download e-mail to my laptop and then read it while Im off the networkfor example, when Im in a room that doesnt have wireless connectivity or when Im flying off to California.

One problem that I have with Gmail is its incompatibility with other e-mail systems: Gmail does not support either POP or the increasingly popular IMAP mail protocol. As a result, I was unable to use Gmail with my Treo 600 using Sprints wireless network. Google has said that it intends to support mobile devices directly before the end of the year. But the lack of IMAP support means that I cant easily transfer e-mail messages to or from Gmail the way I can between other IMAP-based services.

As my last note of singing Gmails praises, I need to point out that it seems to work equally well with practically every other browser that Ive been able to throw at it, including Internet Explorer for Windows, Apple's Safari for MacOS 10, and Mozilla Firefox for both. This is no easy feat for an application this sophisticated in its use of JavaScript. Google has clearly gone out of its way to show that complex Web-based applications can be developed and deployed without relying on all of that Microsoft-specific junk thats been crammed into IE. Other websites should take notice.

Many companies will probably decide that Gmail is not appropriate for business use, since businesses typically want to maintain control over their own e-mail. Perhaps Google will bring out a version of Gmail running on an appliance, the way the company now sells a search appliance. But the idea of search-based e-mail is catching on. Bloomba, for example, is an e-mail client that offers many of the searching, spam protection, and automatic message filing that Gmail hasbut it works with any POP or IMAP-based account. As with Gmail, you just click a file button when you are done reading a message with Bloomba and the message is filed; you get your filed messages back by using search.

Gmail is going to make a big impact, and e-mail will never be the same. But Gmail also proves an argument that Suns been making for more than a decade. I wonder if they will exploit it.