About a month after receiving $2 million in angel funding, ScanScout, a Cambridge, MA-based start-up that tracks online video by topic, has closed $7 million in first round funding. The round was led by General Catalyst Partners, with previous investors Ron Conway and First Round Capital also participating. The financing will be used to support product development and staff additions. The company, which was founded two years ago by two former MIT students, officially launched earlier this month. ScanScout monitors the content’s spoken text, audio and images and then select related advertisements that run just below the video screen. Release