I have mixed feelings about Media Lab. They were the cool thing at one point but, even with their expansion, they just don't seem to be much in the conversation any longer. That's not necessarily a bad thing--a lot of academic matters aren't--but they certainly aren't the focus of conversation they were at one point.
Locu. Acquired by GoDaddy. Morphed into a Yext competitor called GetFound.
I took a class co-taught by TBL called Linked Data Ventures (6.898). There was an effort to seed a Semantic Web startup ecosystem with project teams formed in the class. IIRC one of the groups did get funded and was eventually acquired, but not using Semantic Web/Linked Data.
Regardless, it was an amazing experience having TBL review our little demo app.