Anna Gunn, just off her Emmy-winning role as Skyler White in "Breaking Bad," has taken to the New York stage to launder herself, so to speak, from the character she played for five seasons. In "Sex With Strangers," opening July 30 at Second Stage Theater, she portrays a woman with a fear of the Internet and the anonymous vitriol it can spew. Ms. Gunn, who was the subject of anonymous Internet attacks while playing the morally ambiguous wife of TV's most beloved meth kingpin, is very comfortable with the material —maybe too comfortable. Facebook pages, websites and message boards devoted to passionately...