marxists.org is a devoted, specialized resource website with all sorts of fascinating primary-source material on one of the most consequential ideologies in modern history. I have it not only bookmarked, but in my bookmarks toolbar, right between biblegateway.com and jisho.org. Upworthy is vapid drivel. This isn't a contest.
I assume there's better content on it than the unreadable crap Snowstalker keeps linking to then?
I'm kind of surprised, you seemed like a potential Upworthy fan. I'd also wager that based on Facebook shares, it seems to be the most popular website amongst people at my church FWIW.