Quantcast, a San Francisco-based web analytics company, says it has raised $27.5 million in Series C funding. Cisco Systems (s CSCO) is leading this round of funding which also includes funds from previous investors Polaris Venture Partners, Founders Fund and Revolution Ventures. Quantcast by now has raised close to a total of $50 million in funds. It has built up a massive infrastructure that allows it to measure digital audiences. I’ve always liked this company — its Quantified reports are more meaningful than some of the arbitrary numbers thrown around by other last-generation measurement services.