I'm looking for privacy-enhancing and ad-blocking methods. On the desktop there's the Ghostery extension which works fine in Opera. But when you try to download the extension on O12 mobile, it just does that: download and save, but no installing. Are extensions simply not supported?

Content blocking however IS supported. I've used one of the list of http://www.fanboy.co.nz/adblock/opera/. To try it, simply store the file in ~/.config/operamobile-labs/urlfilter.ini.

This works great, but makes Opera start up rather slow The list is very comprehensive and tries to minimize false positives and negatives, which is probably the culprit. Are there more compact lists available? I'm more interested in blocking the worst privacy risks like facebook and google while maintaining speed, than occasionally encounter an add or inadvertently blocked page...