This is the site:

http://www.longroom.com/polls/methodology/

This is what it looked like in 2011, and I don't see any valid snapshots of the site in its current form until March of this year.

As you can see from their methodology page, they're pretty vague as to the specifics of their model, other than claiming it "uses the latest voting data from each state's Secretary of State or Election Division."

The graphs below cover the last three presidential elections and show the LongRoom Polling Analysis of polls for those elections. In all cases, the LongRoom Analysis was accurate to within +/- 0.3%.

They used their "exclusively data based" model to analyze the polls for those elections well after the fact.

So essentially they have a short page that says "we use the data and our model retroactively called the last 3 elections within 0.3%. Trust us guys."