I think for both agencies and little guys, this is outstanding news. I’ve said before that I think some bad behaviors by little webmasters tends to occur from good intentions (the road to hell, etc.). Having clear communications when these good intentions really do lead into hell will benefit the perpetrators, and hopefully improve overall content quality within SERPs.

As far as agencies are concerned, I already think Webmaster Central gives the agency a better view of what the client may be doing on their own, especially as far as ill-conceived (well undoubtedly well-intentioned) independent link-building is concerned. Having a formal communications channel when penalties or removals occur helps deal with client confusion, and to deal with the inevitable questions:

• “You’re an SEO. Can’t you just call someone at Google and have them fix it?” (no)
• “How can you tell I’m penalized?” (duh, check your traffic and indexing)

Ought to be fun to see how this develops…

I think even in the biz, black hat is an overused phrase. I’ve always assigned technical prowess and intent to deceive to black-hattery. Keyword stuffing is amateur-hour stuff.

Here’s how I would break it down:
Black Hat:

• IP addressing
• Cloaking
• Squatting (where it requires server exploits)
• Scripting exploits
• Certain types of doorways

Dunce Cap:

• Keyword stuffing
• White-on-white text and links

The thing is, a lot of black hat tactics are either smart, or require some sense to make work. Dunce-cap tactics are the sort of thing anyone’s technophobic great-aunt could execute, and are dumb ideas to boot.

Personally, I prefer to be a tinfoil-hat SEO. The tinfoil protects my brain from rays emitted by Google’s Earth-orbit satellite data centers, and is a charming fashion statement in years where metallics are considered a must-have accessory.