Sink brings some big advantages to the race, in particular her name recognition and her fundraising network. She also carried the 13th District twice before, both in her bid for governor (when she edged Rick Scott here 49-47 despite losing statewide), and in her successful campaign for CFO in 2006 (when she beat her Republican opponent 54-46). And a snap poll showed her defeating potential GOP candidate Rick Baker, a former St. Petersburg Mayor, 51 to 34.
But Sink also brings some negatives. For one, she lives two districts away and now says she's house hunting in the 13th, which would allow Republicans to drag out the carpetbagger label. (Whether it sticks is another question.) For another, even though she came within a hair of stopping Scott in 2010, she ran a tumultuous campaign and burned through a scary number of senior staffers, firing campaign managers and finance directors.
Still, there's no doubt that Sink's entry will have a major impact on the special, which is still unscheduled. (Officials are reportedly looking to consolidate it with local elections on March 11 of next year.) With a short runup to the election, Sink's high name ID is especially important, and she might even dissuade some Republicans from running; so far, only ex-state Rep. Larry Crow is running.
There's also the matter of the Democratic primary. Attorney Jessica Ehrlich, who gave Young his closest fight in ages last year and was the only Democrat to announce for a rematch, is still very much in the race and has even picked up at least one new endorsement from a labor group. But that same poll gave Sink a dominant 63-20 lead over Ehrlich for the Dem nomination, so as painful as the thought may be, she might want to consider parlaying a graceful exit into establishment support for a bid for lower office. (Even Ehrlich seemed to acknowledge this possibility, saying before Sink's announcement: "Right now I am running for Congress.")
Other Democrats are likely to clear the field for Sink, but there's also one more thing to consider here: Whoever wins the special election will have to run again next November as well. That gives folks on the losing side a second crack at the winner, so a new batch of names might emerge next year after the special is resolved.