Westeros.org's unique trait was that they tracked down and documented every little word Martin ever said. It was basically the intellectual equivalent of stalking. This led to the birth of the "So Spake Martin" collection. "The idea [behind that] was it's a collection of correspondence that George has had with fans, interviews with various places, online chats, all from the late '90s, early 2000s. And we realized, hey, these are going to get lost."
Elio and Linda did such a good job of keeping an archive of Martin's ideas that Game Of Thrones showrunners David Benioff and Dan Weiss joined the site while they were planning the show. They mined the brains of the biggest Ice And Fire nerds on the planet to help them cast their new series. "They hung out for a while, they answered some questions, and asked for ideas, like, 'Anything you guys want to see happen, any actors you want to see?' Jason Momoa, who played Drogo -- they didn't know anything about him, and they started looking at him thanks to fans at Westeros.org pushing pictures of him and saying, 'Look at this guy, he could totally do it.' Charles Dance, same thing, everyone was saying he should be Tywin."
Today, Elio maintains that the site is very much focused more on the books (he himself stopped watching the show after season five). Plus, he and Linda have been very critical of the show's direction and how it's spoiled aspects of the books.