Can a person legitimately fall in love with another person that they haven't met other than online?

Why not? Sometimes those relationships are more intimate because you really get to know them.

We must consult the love police!

I wonder who gets to determine what is " legitimate or not....yes I think you can but it comes with questionable odds of success.

Yes, apparently people do. (For a good pre-Internet example of this, you can read a book called [i]Shakespeare & Company[/i]).

But..I am really not so sure that falling in love itself is so legitimate, considering how unstable such feelings are, how fast they fade, and how little they count in the long run.

Yes.