Why are Facebook pages/groups on other websites now?

[Stranger]

I always see "John Doe likes _____ *on Cool likes." Or "on FBlike," or countless other websites. I stopped joining groups when this started happening. Why are all of the pages on these sites?

[Daniel]

Oh, that pisses me off so much. I have to go and search up actual pages, make sure its part of facebook before I "like" it, make sure it doesn't send me to another website. I feel like throwing a brick at my pc when I see those websites, especially the ones identified by a heart.