Where does Tumblr fit in your marketing channel pipeline?
Think of Tumblr as the traffic generation engine, much like expert Q&A site Quora. Tumblr's strength lies in directing traffic and has build-in viral factors: easy share easy fav.
Tumblr is a Gif Heaven
Gif's work extremely well on Tumblr and Tumblr handles a lot of gifs really smoothly. Meme, humor, comic strips... also preview of action films, animations, cartoons work extremely well on this platform.
Tumblr themes are stunning. Instantly make your blog look professional
I really enjoy the wide selection FREE themes on tumblr. These themes are so amazing, I can get a great look in minutes. I also think the way Tumblr posts are formatted make the website look consistent and effective.
This is a tough one. Tumblr was going to experiment with ad publishers but then decide to discontinue. There are some hacks to display Adsense, so far I haven't personally made any to work. Technically Amazon Native Ads also works on Tumblr, have not tried it myself.