Not new, but notable: Tumblr foraying into paid ads

[foxfirefey]

Tumblr annouces foray into paid ads (Adage)
Can Tumblr’s David Karp Embrace Ads Without Selling Out? (NYTimes)

Tumblr is a microblogging platform that has had a LOT of VC investor dollars put into it before it had a monetization strategy.