Microsoft bought this product from Sybari and is incorporating it into several of it’s products including Exchange and SharePoint. It can also be used to keep an eye on IM clients. I also believe it will be able to be integrated into ISA Server 2006.
Microsoft is really pushing Antigen which will eventually be known as Forefront. Go to any MS event or an event that MS attends, and you will find lots of literature and MS staff talking about it. Ballmer states it as one of the main players in MS’s security strategy.
Sybari currently makes Antigen for Lotus Domino. It will be interesting to see if MS kills that line.
Don