Symantec buys firm that blocks spam TurnTide Inc., of Conshohocken, which targets unwanted e-mail at the source, brought $28 million.

Haldeman said the TurnTide deal closed on Wednesday.

TurnTide has fewer than 20 workers, and 10 to 15 employees will be absorbed by Symantec, Haldeman said. She said she did not know whether the workers would remain in Conshohocken or be relocated.

Symantec, which is based in Cupertino, Calif., and makes the Norton line of Internet security software, plans to offer TurnTide's technology as an additional service to customers.

"Spam is a problem everyone has," TurnTide cofounder Josh Kopelman said yesterday. "Over 200 companies are trying to solve it. TurnTide is solving it through a fundamentally different way, instead of masking the symptoms."

Kopelman made a big splash in the tech world after founding Half.com Inc., the fixed-price consumer sales site in 1999, and selling it to eBay Inc. less than a year later for more than $300 million.

Kopelman and other area tech high-fliers - Lucinda Duncalfe Holt, formerly of Internet consulting company Destiny WebSolutions, and Vincent Schiavone, chief executive officer of the Paoli-based tech incubator ePrivacy Group - launched TurnTide in February.

Symantec, a publicly held company that had $1.87 billion in revenue in its most recent fiscal year, learned about TurnTide from being a customer itself.

Contact staff writer Wendy Tanaka at 215-854-2752 or wtanaka@phillynews.com.