Source : Search Engine Watch | ForbesThe three major search engines are determined to one up each other in the free email arena in terms of mailbox size and features.

Yahoo has expanded capacity and significantly upgraded the performance of its email system, making it a viable alternative to Google’s Gmail service.

Users of Yahoo’s free email service now have 100 megabytes of free storage,(expanded from 6 megabytes previously), and the maximum message size has been increased to 10 megabytes. Yahoo has also improved the back end of the mail system, putting a greater emphasis on search and dramatically improving system performance.

MSN’s Hotmail, the previous email leader, plans to increase the amount of storage for its free Hotmail account inboxes to 250 megabytes, (up from just two megabytes). Users also will be able to send larger attachments, up to 10 megabytes.

Google’s yet to be publically available Gmail service, has 1000 megabytes of free storage, and boasts the best searching capabilities.

All three offerings are supported by advertising, Yahoo and MSN in the form of banner ads related to geographic location, while Google utilises its own AdWords product basing placement on the content of individual emails. This targeted ad serving has caused privacy concerns, the major reason why you can only subscription is currently only by invitation.

A great summary of each free email providers features can be found here.