Google AdWords and MSN adCenter follow the same approach for PPC platforms, using essentially identical match types, but Yahoo Search Marketing is a little different. Diana Adams lists the three match types. Definitions and examples follow, providing examples of how the match types might work with different search phrases.
How you use match types will affect the number of impressions and click-throughs you get. Broad matches receive the greatest number of impressions, because the terms you're bidding on can appear anywhere in the searched phrase, yet broad matches will have the lowest click through rate because your ad may not be relevant.