What, criminals don't obey court rulings? I'm shocked! (The US FTC supposedly put these guys out of business two months ago: http://www.ftc.gov/opa/2008/12/winsoftware.shtm) The good news is this is not a true "exploit" in Firefox, but it is abusing website features to browbeat users into downloading their executable -- you can simply refuse although it may screw up your browsing session. The bad bews is we haven't yet figured out how to limit abuses of these features without breaking legitimate websites that rely on them.
I'm slightly discouraged by the fact that the "duplicate bug" was marked 2008 with no fix yet. As I'm sure you understand, the _only_ way to exit this website is to terminate firefox as an application. Innocent users wouldn't know how to do this and would literally be forced to install the malware or hard shut down their pc.
Would you be happier having this bug duped to a 2006 bug? ;) In bug 331334 comment 13 I explained why this is bad, and in bug 331334 comment 4 I suggested some solutions. I'm hoping that in a few weeks, when we're done fighting the Firefox 3.1 fire, we can take a step back and decide which [sg:moderate] and [sg:low] bugs are "beginning-of-cycle" bugs and worth working on for Firefox 3.2. The badgering issue will almost certainly make the cut, since it is actively exploited in the wild!
I may surprise you but there are many ways for a "DOS" attack against browsers, there are other examples like bug 61098 which is from 2000 (unfixed) reduping to bug 432687