To illustrate my problem, I'll use an ecommerce book store.
On the search results page of this site there are 30 items. Each item has a link to the book detail page, and directly underneath is another link to an author search for each book.
If you click on the author search, you get a page of 30 products from that author. So now this page has 30 identical links pointing to the same page - itself.
My question is this: Would it help seo-wise to change those author search links to plain-text on an "author search"? In other words, does plain-text text count more for on-page keyword density, relevance etc.? Or does having all those links pointing (voting?) for the same help that page?
Thanks in advance to anyone who's slogged their way through my ramblings :)
I suggest not linking a page to itself whenever you can avoid it. The anchor text "might" help the page as an on-page factor, but I believe it's more likely to trigger a problem, especially when it's done to the extreme - and 30 times would be an extreme.
As a general rule, anchor text has more punch than plain text - but don't think from the "keyword density" point of view. That's a webmaster metric that helps you see if you've gone over the top or not, but it's not a metric that is directly used in today's algorithms, IMO.
I often place frequently repeated text in an image rather than lod up the page (learn more, examples, related pages, etc, etc.) It's important to keep the semantic, relevance signals of a page as clean as we possibly can. It helps Google to do its job better.