All first-year law students receive computer accounts in August. When you register, the campus Information Technology department creates several system accounts for you: email, shared disk and web space, computer lab login, student registration system, and so on. Your email address will take the form "firstname.lastname@example.org," where "jsmith" is your computer login account.
All student email accounts are actually handled by Google's Gmail system, though as you can see, "gmail" doesn't appear in your address. Moreover, you don't log in or access these accounts in the same way you would for an ordinary Gmail account. For more information, see this page by the campus I.T. department.
Law students are required to check their William & Mary email at least once a day.