According to dozens of Google-watchers, Google’s ad-driven email system, Gmail is slated to move from beta to live-status on Friday April 1st, one year after it was introduced to a limited number of testers. On its first day, many thought Gmail was an April Fool’s joke.

To establish the initial beta-test group, Google issued a number of initial invitations to a very small group of users that day. It also sent each of those users six invitations to send to friends who where also issued six invitations with their beta account. Gmail grew its potential test group by a factor of six every time it gave away a new beta-account. For the past two weeks, Google has been randomly inviting users of its search engine to sign up for Gmail accounts with a discreet link that appears for about 1 in 100 users.

Gmail is one of Google’s most successful new ventures offering users a few features rival programs Yahoo-mail and MSN’s Hotmail simply can’t match.

First of all, Gmail offers users up to 1-gig of free storage space, making it useful as an online filing cabinet of sorts. Once the realm of text based messages, Email has become the most common means of transferring various files from one computer to another. These messages are growing in size as Internet users and their personal technologies become more sophisticated. Today’s typical email message is often hundreds of times larger (by data volume) than a typical email message two years ago with images, music clips and cell-phone generated movies moving through they system.

Next, Gmail has an excellent search feature that efficiently interacts with Google’s Desktop search tool. Following the principle that information is information regardless of the media, Gmail and Google Desktop combine to make a deceptively simple but very powerful information management resource.

The last feature Gmail offers is more of a price than a privilege. Gmail serves as a billboard space for AdWords advertising. Ads appear to the right of the text much like they do beside Google’s search engine results. Ad distribution is based on keywords or word-groupings found in the text of emails, which means active scanning each piece of mail sent through Gmail to determine which ads to serve to each user. For SEOs and SEMs, Gmail offers a personalized glimpse of how Google matches ads with text. It also offers a lesson on how powerful Google’s AdWords program can be. If millions of users start to use it, Google gains billions of new units of temporary real estate to display AdWords on. Try to imagine the number of ads you might be served each day if you were a Gmail user…

Gmail currently enjoys the dominant position in the use of email as an advertising deliver system. It gives Google’s AdWords program another advantage over rivals at Overture (Yahoo) and MSN but that advantage may only be temporary. Both Yahoo-mail and MSN Hotmail seem ready to match Google gig for gig and ad for ad in the near future.