Imgur's users are pseudo-anonymous, just like reddit and HN. Advertisers aren't really willing to pay much for that when they can target accurate user profiles like Facebook or anything that connects with Facebook.
- facebook
- twitter
- amazon ads
- google ads
- quantserve
- google analytics
- scorecardresearch
Because this is pretty much the standard list for any major site, each of those providers has a highly detailed profile built for the average web user. While the top three will often have login data associated, there's plenty of capability for data mining without that. This excludes data other providers can glean from the actions taken and data rendered by those top three providers - I haven't kept up on the state of that and I don't know how possible it still is.No one is arguing that facebook/google/tw... (well maybe twitter heheh) aren't profitably mining lots of user data. But imgur probably isn't able to mine much value out of it's own data.
The bottom line is imgur's data is probably not worth much, what _is_ worth a lot is imgurs traffic, and that traffic is taking a hit from adblock.