What are the factors that go into determining the PageRank of a Twitter page?

Matt's answer:

We have a Twitter question from Atul Arora  of Fremont, California who asks: What are the factors that go into determining  of PageRank of a Twitter page,  e.g. is it the followers, backlinks? I gave an answer about Twitter where I said that  we treat Twitter pages just like regular web pages. So, it’s the exact same thing – we don’t  look at the number of followers you have on Twitter,  we look at the number of links that you  have to your profile or to your specific tweets. So, you know, if we have a lot of PageRank  or a lot of linking to one particular interesting  status message that one might be more interesting  or more likely to show up in our search results. But we don’t look at, you know, how many  followers you have or anything like that.  We’ve certainly seen that followers can  be gamed pretty easily on a lot of different sites. So, what we find  tends to be backlinks and the reputation  of those backlinks is the way that we score  how reputable a page is –  on Twitter just like on any other site  across the web.

by Matt Cutts - Google's Head of Search Quality Team

Original video: