Siga Technologies, a company with both instant messaging and biotechnology products, signed a binding letter of intent to acquire Hypernix, the Tel Aviv-based maker of the Gooey chat application.

Gooey lets visitors to particular Web sites recognize and chat with each other. Other companies providing similar technology include CrowdBurst, Odigo, NetDive and SideTalk. America Online is at work on similar capabilities for its own instant messaging applications. Hypernix shareholders will get 3 million shares of Siga common stock under the terms of the letter, and Siga will assume $1.25 million of Hypernix's debt. CNET Networks, publisher of News.com, last year paid $2.64 million for a 4.25 percent stake in Hypernix, according to a company press release. In November, the company received an undisclosed investment led by New York investment bank Allen & Co. and Japanese venture capital giant Jafco. Gooey, the first among a crowd of so-called cobrowsing technology providers, recently acknowledged serious financial difficulties, closed its New York office, and said it was looking for a buyer. The company says it has 900,000 registered users.