[wonderwes]

There is some truth. Packet sniffing is a very valid problem with the net. Now will it happen to you? Unlikely. Though people with the correct network experience, and proper access could sniff your packets to see everything you do on your connection. From a webpage you load, to any IM chat.

Everything you see on the net is traveled by internet packets. No matter what format of data.

For poker software. It still is data being sent from the pokersite to your machine. Either its an encrypted packet or a normal packet. Like when the dealer chat is all text based (dealer chat states every move). A normal packet, someone could determine what the text was. This is why every commerce website (amazon, newegg, etc) is heavy in stressing their 40bit or 128bit encryption for anytime you use the purchase form for a product.

For the trojans running on a computer, anything is possible esp now with XP boxes having remote management. A trojan can just be a registry or an .exe set to run at the right times. Once it is running in system memory, who knows what it was designed to do.

It never hurts to virus scan, and it always benefits to have some type of firewall/proxy setup.