For that specific situation, this wouldn't help too much, seeing as the up-loaders are already removing source info, so it's reasonable to assume they will fudge the image somehow to change the hash value.
4 karma · joined April 11, 2011
No way to filter just rage comics unfortunately without cooperation of their creators(title tags on them so you can filter).
Unfortunately you are right for the overwhelming majority of users who will see "LastPass Hacked!" then note "Don't use LastPass".
I wonder what's with the confidentiality at book search. The first two things that pop to mind is keeping the yellow badges secret and preventing their enemies from messing around(publishers are pretty mad at the whole book scanning thing).