One of the best features of using ISA server on top of the additional security is the fact that it gives you full control of web traffic. For any corporation on of the problems is balancing employees needs for internet information with time wasting internet surfing. Inorder to help reduce this here are some steps to block specific websites in ISA Server. I have also attached a blocked list export which contains some common problem websites to get you started.

1) In the ISA server management console, click Firewall Policy
2) On the Toolbox tab on the left side right click the "URL sets" folder and create a new url set
3) Once this is created right click on the new url set name and choose "Import to selected"
4) browse to the lcoation of the xml file downloaded from this post and import
5) Create a new access rule called "Blocked Website"
6) Under the selected protocols choose FTP, HTTP, and HTTPS
7) Under access rule sources choose Internal, localhost, and VPN clients
8) under access rule destinations choose, Url Sets -> "the name of your blocked websites set"

then just apply and enjoy!

File Attachment(s):
ISA2006_Blocked_WebSites.xml (290kb) downloaded 2 time(s).