You're required to conducted a particularized determination, according to Bruno & Stillman, 633 F.2d 583 (1980). So not everybody's going to agree on whether Sandra Fluke is a limited public figure.
And the fact that everybody knows who she is now doesn't help Limbaugh. The question is whether she was a limited public figure when she completed her presentation, and before Limbaugh launched into her.
That's because, if the main controversy that made the person a public figure is the alleged defamation itself, then the defendant can't point to that controversy as making the plaintiff a limited public figure. "Those charged with defamation cannot, by their own conduct, create their own defense by making the claimant a public figure." Hutchinson v. Proxmire, 443 U.S. 111, 135.
BS. Fluke postured for her position on TV before Congress. She is a public figure by any definition. She wasn’t summonsed to Congress. She wasn’t forced in any way to be on TV. She, herself, claims to be a public advocate. She also advocated using public funds for her sexual entertainment on broadcast television before Congress. Sorry, but you can’t lay claim she is a private person.