-----------------Updated June 2017--------------------
An updated version of this Community Guide is now available, click here to view.
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Whether you are new to Airbnb or an experienced host, I recommend getting recommendations from friends, family, colleagues or past guests who might not have booked through Airbnb. All you need is the person's email address or if you have your Facebook account attached to your Airbnb account, you can send requests via Facebook.
Here is a "How To" guide for getting references. It is important to understand that in order to get a reference, the person referring you will need to already have or sign up for an Airbnb account. When a person provides a reference, you have an opportunity to accept or decline the reference.
To get to your "References" section of your profile, go to "Profile" and then choose "References" from the left hand side menu.

Adding References Using Email Addresses
To send emails to friends, enter the email address(es) into the box and select request. You can also import your contacts as well but you will need to have a .csv file ready to import.

When you send the request, the person providing a reference will get an email in which they will click on a link and then be required to sign up on Airbnb to provide a reference. The email they receive looks like the one below.

Adding References Using Facebook
When adding Facebook friends, you can add them by selecting "Create Request" which will load a window where you can choose your Facbook friends and type in a message. Once again, they will then need to sign up for an Airbnb account.
You will also see a list of friends, and their Facebook profile photo, who already have Airbnb accounts. For those friends, you just need to choose "Request" under their profile photo and they will receive a request for a reference.

Happy hosting!
Dave