What does it mean to be waitlisted?

Basically, you are rejected, but in order to be seen as "more inclusive" college, many schools place big number of students into waitlist. Since quite recently, liberal arts colleges are giving "hope" to thousands of applicants by putting them into waitlists. I wouldn't expect anything positive if I was waitlisted from LACs, unless it's CMU-Q. As I know, they consider uzbek applicants as potentially suitable for the campus (due to current students' and alumni's good reputation), and their waitlisting system actually works. 
In short, don't expect too much if you get a decision with waitlist on it.