Wow, this is a really interesting play by Facebook to gather finance details of their users. I can absolutely see an scenario where friend X wants to pay friend Y who hasn't enabled Pay and they nag until friend Y does sign up. The cycle will continue. It's probably part of a bigger venture into eCommerce for Facebook.
I think they're aiming to enable people to buy from ads without ever leaving Facebook. Reduces friction for the buyer and has the potential to be a major source of revenue from ecommerce companies.
I'm sure they realize how much money Google is printing with their shopping campaigns, and FB ads haven't proven to be very rewarding for ecommerce outside of fashion/lifestyle. Adding a major feature like that would be enormous in grabbing some of that market.
User-to-user is just one piece of the puzzle. Facebook has faced a REAL uphill battle convincing advertisers of the value they add in the path to conversion. Anyone who is familiar with cross-channel attribution knows this all to well. Many of FB's recent updates have been big slaps in the face to many advertisers, but this could be a huge win.
It would in essence enable them to go from being what is typically one of the first points in the "generating awareness" stage to being a last touch success. Most advertisers are not savvy to things like attribution (hence one of the reasons AdWords still focuses on last click in their main UI), so being able to say to businesses "here is how much money you earned directly and immediately from your ad" is a huge win for proving the value they add.
Any PMs or engineers at FB--would love to chat with you about this and how it ties into the attribution picture. Seriously--it's a huge problem for you right now.
Despite gmails best efforts to block the dozens of emails offering to send me money, I still get a couple once in awhile, and like most internet users I'm pretty good at deleting them without falling for the scam.
I suspect life will be very rough on early adopters.
