A good friend of mine who winged me for day game during the summer would often close with facebook instead of numbers. It's more laid back compared to asking for a number straight up, since the typical number close can easily trigger a shield from the girl. He would often 'escalate' it to getting a phone number anyway.

"It was nice talking to you but I've gotta run. You've got facebook? Here, write down your name" [ pulls out phone and she types in her name], and then judging how down she is, he would also usually get her to type her phone number as well.

When getting the number, he'd have his phone out and say "you're a 613 area code right?" (or 514 or whatever, depending where she said she's from if a tourist). If a girl just said "uh, yeah" without giving the rest of her number, he would reply with "Alright cool, so if I just dial 613 I'll get to you?" to which she'd laugh and usually give him her number.

Like I said, it's less direct and she's less likely to put up a shield.

Yeah, I think facebook close can be better in some cases. Even if she ends up flaking you can still become friends and that opens a whole new social circle because you can meet her hot friends