I hope it's a good sign for you. They may be more into you than you think.
I'm very interested in what it is we do to ward people off. I think I make people uncomfortable when I talk to them, because I'm uncomfortable and they pick up on that. My anxiety is infectious, even when I'm not even conscious of it.
I wish even more now that I knew what you're like in person, but: do you cross your arms? Do you lean away from people? Look away from them? Are you tall? Height can intimidate. (This probably deserves a whole thread to itself.)