Tumblr is a blogging platform and a social network. Your posts get distributed and liked and reposted just like on Twitter, but instead of displaying 140 characters you can display unlimited text, images, animated gifs, photosets, audio files, videos, and more. You can follow whomever you like and get a beautiful dashboard that streams the content you’ve selected throughout the day. It’s a network of over 50 million blogs, and a great place to build a readership for your books or just your daily thoughts. My Tumblr tends to be about books, feminism, cooking, nail art, and Veronica Mars.
After some urging, I've just started a Tumblr blog, Angela Booth's Writing and Reading Life.
(Yes I know -- ANOTHER blog...)
Very nice -- I like it. :-)