I certainly still do. I think there's a pretty regular crowd of people I see in the quest forums that still do, as well.
Beyond being a page view bump, there's a couple of other serious benefits I've seen for participating in questing over the last year. One is expansion of the wiki and to a lesser extent, promotion of the hard work that many screened denizens have put in to it. This may sound similar to page views, but since the wiki is user powered, there's an important distinction in providing incentive to help this endeavor grow, and in giving users the impression that their 670 point bomb on Aston Martin
will ever be seen...ever.
More importantly is the sense of community the quests drive, even if in a limited number of people. One of the most fun moments for me in the first year of screened was the ridiculous level of cohesion it took within the community for many of us to pull off the Stalker Status quest. Beyond the initial connection, many of us that struggled together on that venture still follow one another, still care what each other has to say, and have had many wonderful conversations thanks to that experience.
Also....they're just fun.