To quote what Yahoo! considers unwanted:

"Some, but not all, examples of the more common types of pages that Yahoo! does not want included:

Pages that harm accuracy, diversity or relevance of search results

Pages dedicated to directing the user to another page

Pages that have substantially the same content as other pages

Sites with numerous, unnecessary virtual hostnames

Pages in great quantity, automatically generated or of little value

Pages using methods to artificially inflate search engine ranking

The use of text that is hidden from the user

Pages that give the search engine different content than what the end-user sees

Excessively cross-linking sites to inflate a site's apparent popularity

Pages built primarily for the search engines

Misuse of competitor names

Multiple sites offering the same content

Pages that use excessive pop-ups, interfering with user navigation

Pages that seem deceptive, fraudulent or provide a poor user experience

Yahoo!'s Site Guidelines are designed to ensure that poor-quality pages do not degrade the user experience in any way."

As you can see, there is a lot of grey area here. While most points are pretty straight forward, some like "Pages in great quantity, automatically generated or of little value" could include dynamically generated database driven pages (like a storefront or e-commerce site) while "Excessively cross-linking sites to inflate a site's apparent popularity" could include sites which use legitimate link building strategies to help their rankings.

So what do you do? How do you know if your site falls into these categories? In other words, how do you determine if your site may be considered spam?

I would suggest taking a critical look at your site. Does it follow the guidelines listed in their help section on pages which Yahoo! does want included in its index? For example, are they original? Built for humans primarily? Contain useful information? These are all questions you need to keep in the back of your mind as you assess your site.

If you have concerns that perhaps you could be violating some of these rules, perhaps you need to look at what is needed to ensure you are in full compliance with Yahoo!'s recommendations. I would strongly suggest you do this review. If you do get removed from the index because of the spam policy it could be very difficult to get re-indexed according to Yahoo!'s own spam police.

So should you convert your dynamic site to static?

The simple answer is no. There is no need to scrap that content management system you've likely spent months and years developing. Perhaps simply adding more useful content to some of the pages is all that is needed. By following Yahoo!'s own rules you should be able to reconstruct some of your pages to ensure they don't get banned.

Does this mean you should quit doing link building or remove your links page?

I don't think you should discontinue link building, but if you are doing reciprocal linking, take a look at the site to which you are linking as well as those sites linking to you. You may need to reassess the quality of your link partners using the same tests you put your own site through.

With regards to your link partners, again, assess them for quality. Are they in related industries? Are they worthy of linking to? That is, do they also follow the Yahoo! guidelines? If not then perhaps you will want to consider temporarily removing their links from your site. You may even go so far as to contact them and suggest they perform their own analysis of their site based on the new Yahoo! rules.

So what if you think you have already been removed for this reason?

There is an email address (webmasterworldfeedback AT yahoo DOT com) to which you can send a request for review. This is only a temporary fix, as they plan on implementing a full review process in the coming months.

Also keep in mind that Yahoo! search is still in its infancy. As time goes on it will get better. Perhaps their filters are over filtering sites which are legitimate, but it should get better with time. They can't anger too many people early on, as they are trying to build a competitive search engine. If they start alienating webmasters or legitimate site owners they risk losing search customers to other engines such as Google or MSN.