As there was no video retargeting at the moment (and still there is extremely few), I found this a probably profitable concept and was fascinated by the technical approach. Unfortunately they burnt through the money very quickly by trying to also build out their own retargeting infrastructure instead of focusing on their product.

Only invest in companies if you have enough time to work with them and make sure they concentrate on their specialty instead of wasting money on processes/products freely available in the market.