– Alastair Goldfisher is the Editor-in-Chief of the Venture Capital Journal and contributor for PE Hub, both Thomson Reuters publications. This article originally appeared on PE Hub. –

BlueRun Ventures, Ignition Partners, Founders Fund and angel investor Scott Banister (co-founder of Zivity) joined a $15 million Series C round for Topsy, the San Francisco, California-based company announced today.

Western Technology Investments joined the round, which brings to $30 million the amount of equity and debt that Topsy, a provider of real-time search engine services, has raised since 2008.

The company, which competes against Collecta, Crowdeye and TweetMeme, among others, says that the round of funding validates its social search services found on Topsy.com and used by media various sites, such as those operated by companies IDG Media, The Huffington Post and Discovery Communications.

Topsy analyzes social graphs across social media networks like Twitter (which sees 100 million tweets a day) to rank search results within seconds of being indexed. It can show what people are talking about in real-time. Topsy, whose founders previously launched anti-spam company Cloudmark Inc., counts angel investor Ron Conway as an advisor.