Just being real and honest here because I have had a Tumblr since forever. But if you plan making a Tumblr to post and share your videos, they most likely won't be viewed. A lot of people on Tumblr are there for the gifs and pictures and fandoms, so it's like a getaway from the real world. That sounds super weird, but I can't really explain it. I have tried sharing my videos there, but no one even cares or notices xD There's really no point unless you have thousands of followers, which is hard to do unless you're extremely hot/sexy/attractive or if you're a guy/girl who posts a lot of life relate-able things and is original.