I agree with what Christian is saying, but that doesn't make Manson wrong either.
The difference is in the context. There's a lot of nuance to it, but one big piece that hasn't been mentioned yet is that saying things in person allows you use nonverbal communication to signal things you cannot signal in text.
A message like "You're cute. I'd like to get to know you" opens you up to rejection, and a willingness to face this unafraid is attractive because it's a fairly credible way of showing that you must have reason think you're worthy of her - stuff like that. Online, anyone can shoot off a "You're cute. I'd like to get to know you" without having to be able to back it up. Even if you can't say with a straight face that you're good enough, you can hit ctrl-v and send on the hope that she bites anyway - which is why the line won't have the same oomph behind it as it can in person.
There's a lot of data and research on what makes people successful at online dating, but I don't know anyone who actually tried to wholeheartedly apply this to themselves. I decided to be that person: I implemented lessons from data, economics, game theory and of course rationality in my profile and strategy and OkCupid. Shockingly, it worked! I got a lot of great dates, learned a ton and found the love of my life. I didn't expect dating to be my "rationalist win", but it happened.
Here's the first part of the story, I hope you'll find some useful tips and maybe a dollop of inspiration among all the silly jokes.
P.S.
Does anyone know who curates the "Latest on rationality blogs" toolbar? What are the requirements to be included?