I don't see the logo for the marketplace at the top of the page with AdBlock Plus enabled. Given that lots of CDNs still work for me I found this a bit odd, but this is mostly a bug to point it out; not sure how much of a priority this is for Marketplace (I have no idea the number of ABP users there are).
How did you install ABP on Firefox OS?
I mean on my desktop! I go there to submit apps and do administrivia.
Verified as fixed in https://marketplace-dev.allizom.org/ on FF21 (Win 7) with Adblock Plus installed. Postfix screencast http://screencast.com/t/tElzGgce Closing bug.