Windows Live Hotmail launched today in 36 languages for its 280 million users. The new Windows Live Hotmail looks very similar to Microsoft Outlook, but it is web based. Windows Live Hotmail has all the expected functions; drag and drop, right click menus, AJAX style fast refresh, integrated Instant Messaging, 2GB of free storage, and great spam filtering. Webware has a pretty good summary of the new features. 
The new spell checker is very good, automatically checking before sending the message. It underlines incorrect spellings and links to an online dictionary for help. Last time I checked Gmail didn't have a spell checker.
Security is much improved as well. There is a Red, Yellow, White banner across the top of each message giving you a visual cue to how safe the message is. Windows Live Hotmail requires entering a password each time you sign in, and after some time interval of non use requires you to re-verify. This is pretty obvious for corporate email users but not so common with consumer web based email systems.
Windows Live Hotmail has 280 million users world wide. YahooMail is in second place, and I believe AOL Mail has the third highest market share. Gmail trails distantly. The last number I saw was 10 million users but I'm sure it has gained some users since then.
Market share for consumer email is very hard to win, and once won doesn't tend to move. People hate to change their email address because all their friends and business relationships are tied to that address. Think about all the newsletters, company update services, frequent flyer programs, customer alerts, and other things that automatically tie to your email address. People might try to new email service but they won't kill their existing one. With 280 million users and growing, and great market share, Windows Live Hotmail will be around for a very long time.
