Hi Killa,
That is right. It is IE and Firefox specific, while the two varieties slightly differ for each browser. As I explained in another thread's post it is injected javascript for RUM (real user monitoring) javascript, injected in HTML in 6th instances to better be able to monitor user browser behavior.
Why avast, fanboy's list and avg flag it, isn't known to me yet. The code seems with errors and seems to have been launched very recently...
polonus
P.S. Seems there is a Chrome variant also that avast seems to flag...