I see a lot of people talking about Tumblr's userbase rather than the quality and potential profitibility of this userbase. As someone who has worked in brand management at P&G, i do not see any major consumer brand who's personality fits with lol cats and porn, therefore which major brand are you going to find to put ads next to that crap. Secondly lets take a look at the demographics and LSM's, tumblr is mainly made up of teenagers, you need to look at your ad spend relative to the quality of the demographic.

Start a successful extreme sports website and you will find brands like redbull that's brand fits in with your message, start a music sight and you will find a brand like pepsi that fits in well. Tumblr is all over the place, i have no idea how do you control the message? This website was built to just be cool and over the last six yrs they never tried to tie their identity to the type of revenue model they were anticipating. The reason for this is because they did not think of monetization at all. If you started a magazine back in the day, you would choose your segment and also tie in the magazines identity with the type of ad revenue you want to generate like a house & home magazine, you have home depot etc. This is not a billion dollar company. I am rooting for Marissa but her social media profile is starting to look bigger than her bite.

I will also add that Tumblr did try their had at curated content a few months back but decided to scrap the idea. This shows that they understand the need for more quality consistent content but are unable to execute. Flipboard has totally taken them to school on this front by allowing people to create personal magazines and you find a better quality experience. They need to learn some stuff from Flipboard even though it is not 100% comparing apples to apples.