sygate pro 5.5 ?

Hi all started using sygates personal firewall pro ver 5.5
I have a question, what are the signature files you update, what are their purpose? thanx

http://smb.sygate.com/document/ids_signature.htm

It allows the firewall to specifically identify different types of attacks or intrusions.

Thanks fink for the info , I thought it had some kind of AV biult in, well i guees it does somewhat, thanks again for the time and info.