I know reddit isn't exactly a social network, but it fits here best. I'm sure people are aware that if you put "?sometexthere" at the end of your URL (before the hashtag or with an "&sometexthere" if the URL already has a question mark), you can get around the stupidly incompetent repost filters. If you don't, then I don't know why you're even trying. But basically I put "?sometexthere" at the end of all the non-image URLs. I do this because every so often content gets ripped right off a reddit post and plopped into an Buzzfeed/Slashdot/whatever article where the author doesn't even bother to check the URLs. Mainly it's just for personal bragging rights and shits and giggles, but you could probably use it to track the spread and impact of your post as well.