I mention cool sites here on my sites. And, when I use material here from other sites, I attribute it either in the sending or putting a link to the site with the material. I can't possibly pay those other sites for their material so this is the least I can do.
FunnyJunk.com and DamnLOL.com have a business model of stealing artists' material and putting it up on their sites after slathering the material with adverts. The work is unattributed and the advert money does not go to the artist in any way.
The Oatmeal has a good discussion of it here.
I suggest no one click on the above sites since that rewards them. However, if you want to send an email to them, use the email address email@example.com.
Since FunnyJunk uses Gmail you might contact google and at least complain.