Well if such intellectual reading as ....
Why the one you fancy never fancies you.. Murphy's Laws of Love,
is to be believed then...
Our first reaction is from our hormones. Our cerebral cortex came along later and tried to make sense of love. The other things that lead us to love (apart from smell) is clear skin, symmetrical eyes, excellent poise, and the same inter-occular distance as each other.
Having said that and crushed all the romantics.. I think that over the net one call fall into interest, into lust, into friendship, I do believe that love comes later after meeting when all of the above fall into play.