The only type of linking you fully control are the links you have access to. For many, that means the pages on the site they are trying to rank well. So I have a site named abc-company.com and that is the only site I have to work with. The internal link, the anchor text and links you place within that site's pages to other pages within that site, is what you have to manage. At what point can you over do it with the linkage within ones own site?
That is the topic of a thread at Search Engine Watch Forums named How far to go when linking internally? As one reads through the thread you hear about percentages, you hear about research papers, you hear about search theories, and you hear about keeping it simple. At what point does it look to the human eye that you are overdoing it? Is it about percentages or research papers or is it about the human eye?
Well, its both and its also about industry. For example the search term web design won't allow the mass manipulation of internal links to play a roll in ranking. But does the search term gift baskets allow for it? :) I do not know.
There is a lot to take into account, and its not just about if the site looks bad or spammy. It is not just about a percentage of the internal link ratio to external links. It is not just about the last research paper released. It is not just about the industry you are in. Who said search optimization was easy?
Forum discussion at Search Engine Watch Forums.