More delegates are usually won during Super Tuesday than on any other day during the primary calendar. Many believe that if you're seeking the presidential position, then you must do well on this day if you want to seek the party's nomination.
The nature of Super Tuesday, being a diverse and large geographical and social group all throughout the United States, makes it an excellent barometer to a presidential candidate's likability to win the election.
Today's Super Tuesday 2012 totals 410 delegates and will involve contests in: Georgia (76), Idaho (32), Massachusetts (41), North Dakota (28), Ohio (66), Oklahoma (43), Tennessee (58), Vermont (17), and Virginia (49), along with Alaska's two-week-long caucuses, Mar. 6–24.
A complete tabulation of Super Tuesday 2012 results can be seen here.