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Block ICMP
This blocks all Internet Control Messaging Protocol packets into your computer that were not specifically allowed by the rule above it. Mainly, this helps in maintaining a "stealthy" presence. Hackers and spammers often "ping" thousands of IP addresses at a time in order to see who's online - and who's probably not running a firewall.

Block IGMP
This blocks Internet Group Management Protocol. IGMP is a method for administrators of large networks (mainly the Local Area Networks used in offices) to make changes and manage PCs without having to go to each one and manually make changes. IGMP isn't really that much of a threat in and of itself, but there are a few exploits, like the infamous Kiss Of Death, that can cause a computer to crash by sending malformed IGMP packets. Older versions of Windows 95, 98, and 98SE are prone to this.

Block more Winamp/AOL
This is disabled by default. It blocks Winamp's home site (for those who don't know, Winamp is an MP3 player). Some people are concerned about the "phoning home" Winamp does and it has been accused of being spyware. I have not found any evidence of that but if it'll put your mind at rest, enable this rule.

Block Netscape
Netscape has the unenviable honor of being one of the first alleged spyware producers to ever be identified: it was Netscape, along with RealNetwork's RealJukebox (also RealPlayer) that put the spyware and Internet privacy issue on the map. As of this writing, a class-action lawsuit against Netscape is still proceeding in the courts, surrounding the unauthorized sending to Netscape of people's personal info via a feature called SmartDownload.
It is usually disabled by default because versions of Netscape since 4.5 don't seem to do any spying, and many people need access to Netscape's site. However, if you use Netscape, especially a version older than 4.5 (and also newer than 4.79) then you should enable this.

ActiveAgent
This is currently the first of the Advertiser filters. Only a few major ones will be covered at all. There is not much to say about ActiveAgent except that they advertise. Some of the other ad services do data mining/tracking/spyware, so it's advisable to keep these enabled, even if you use DNSKong.

AdBreak, AdDynamix, and Ad-Flow
More advertising services.

Advertising.com
Advertising.com is a major advertising service that also does a LOT of data collection. Most of this is done via cookies (more on that elsewhere on this site) but some is done through software that can also uniquely identify a user.
For example, the popular Opera web browser, since version 5, is ad-supported and uses Advertising.com to serve ads. A unique identifier allows the advertiser to keep track of what ads you've seen and what one's you've clicked on. Opera allows you to fill out your name, address, income, interests, and other demographic information which Opera can havest to learn more about you. (For the record, and greatly to Opera's credit, they do not try to entice you to fill any of this out or even offer it during installation.)
At any rate, it's a good idea to block Advertising.com, although DNSkong with the configuration file carried on the Updates page does just as good a job of keeping the ads and their cookies away too. It certainly doesn't hurt to use both though.

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