Form that allow users to sign in to Facebook or Twitter?

Though I am curious as I am building a lead capture page for real estate forms on my website.  Do any of the forms current have the option to allow a person to sign in by facebook or twitter?  Here is a sample form I found.  Sounds like the effective conversion rates are pretty high

Unfortunately, it is not possible to create any sign in form with JotForm.

Just for you to know, you may like to add a Facebook Like Box widget in your form. This will ensure that the users first like your page before they can submit your form.