^ Yup, this. The heart also draws a more obvious connection to the actual purpose of the teen/adult markers (that being, who you can and can't do sexy RP's with).
Fantasy is my #1; I will give almost anything a chance if it has strong fantasy elements. Post apocalyptic, superhero, alternate history, science fantasy, some supernatural, romance, and a few fandoms (especially Game of Thrones) are also likely to catch my eye.
Celest and Kagayours are correct. Read admin posts in this thread if you want a more detailed explanation of the faggy hearts: SOLVED - Symbol next to username?