AdMeld, an online ad network optimizer, has raised $8 million in Series B funding.  Spark Capital and Foundry Group led the round.    Back in November of 2008, the company raised $7 million from the same investors in a Series A round.

New York-based AdMeld is looking hot right now.  In the past six months, the platform has grown its customer base by 500% and now has around 65 online publishers making use of its technology.  Some of these users include several well known names like Discovery Communications, FOX News, The Huffington Post, IAC, Thomson Reuters and World Wrestling Entertainment.

The startup offers a set of tools for online publishers which optimizes the ads run on their networks, so if something is undervalued, AdMeld replaces it with higher performing ad inventory.  AdMeld says its platform is designed to generate the highest possible yield from each impression and customers see an increase in revenue between 30% and 300%.  AdMeld also provides performance reporting and brand protection tools.

With its recent success and this new round of funding, AdMeld plans to expand into Europe with a new London-based office and Data Center.

Some of AdMeld’s competitors include Rubicon Project and Pubmatic.