hiya old cynic! (lol how are you babes??)....disagree with you to an extent, but you are right in that you can only know so much about a person until you meet them face to face - even if you are both completely open, honest and truthful. So much of what we can read in other people is through their body language, the pauses before they speak, the humdrum day to day incidents, that all tell us alot more about a person than they communicate through words etc. And also, the physicality of someone....guy may be lovely but if he keeps one hand down his boxers 24/7, you might wonder if he's the one of you! Ditto he may smell odd, have bad breath etc
BUT, having said all that, and being a proper grown up (35 good god) not a daft young lassie, I do still believe you can fall for someone you haven't actually met. When you meet them in real life, that will either confirm your feelings, or temper them slightly, but that initial feeling of love is still real, and valid.