It makes your profile / reputation more persistent by creating a durable link to your persona external to the AirBNB system. If I link my AirBNB account to my

It makes your profile / reputation more persistent by creating a durable link to your persona external to the AirBNB system. If I link my AirBNB account to my Twitter account, I can't shirk a poor reputation by simply creating a new AirBNB account, unless I also forego linking to Twitter. Essentially, if my connected Twitter account has 3 years of activity behind it,* it's a somewhat strong signal that my AirBNB account isn't a disposable, since I'm tying my reputation to something that I've invested a few years into, and will continue to actively use. * I'm presuming that the AirBNB hosts would be able to see how long I've had the linked account, and whether or not it's active. Or some other measure of guarding against a fake AirBNB account linked to a dozen fake social networking accounts.