Gmail is a free, search-based webmail service that includes 1,000 megabytes (1 gigabyte) of storage. The backbone of Gmail is a powerful Google search engine that quickly recalls any message an account owner has ever sent or received. That means there's no need to file messages in order to find them again.
The move pits Google even more strongly against Yahoo! and Microsoft, both of which offer extremely popular free e-mail services. It also more firmly establishes Google as a portal, rather than simply a search destination.
One issue that Pamela says creates privacy problems for the new service, is the ability to generate AdWords, like the main search engine, which are relevant to each message. In short, Google's technology will be able to read the content of a message and provide an ad based on this.