Stephanie Courtney (born February 8, 1970) is an American actress and comedian, best known for playing the advertising character Flo in television and radio commercials for Progressive Corporation beginning in 2008, and noted for her recurring roles on several television series, including the voices of Renee the Receptionist and Joy Peters on the Adult Swim comedy Tom Goes to the Mayor (2004 -- 06); Marge on the AMC drama Mad Men (2007); and Diane on the ABC comedy Cavemen (2007). She also appeared in the season 2 premiere of Men of a Certain Age. Courtney is a member of The Groundlings, an improvisational and sketch comedy theater in Los Angeles, California.

Based on this passage, who is the actress who plays flo in progressive commercials? Let's give stream of consciousness first:
The relevant information to answer the above question is: Stephanie Courtney (born February 8, 1970) is an American actress and comedian, best known for playing the advertising character Flo in television and radio commercials for Progressive Corporation beginning in 2008, and noted for her recurring roles on several television series, including the voices of Renee the Receptionist and Joy Peters on the Adult Swim comedy Tom Goes to the Mayor (2004 -- 06); Marge on the AMC drama Mad Men (2007); and Diane on the ABC comedy Cavemen (2007).
So, the final answer is Stephanie Courtney.