Robert_Charlton - 10:15 am on Mar 9, 2012 (gmt 0)
My empasis added...
I realize that page rank can't be "sculpted" by using noindex, and that by noindexing a bunch of product pages, the way that page rank flows through a site would be seriously changed
No, PageRank flow is not something you want to challenge. If you're going to noindex, which I don't recommend, you should use meta noindex,follow... not meta noindex,nofollow.
Nofollow, on individual page metas would also be a serious mistake. I can't see where it is ever helpful except when you don't trust the page you're linking to.
...but what about all the (internal) links back to the category page from the product pages.
Similarly, the nofollow attribute on nav links, which is what I assume this comment is suggesting, is generally a disaster... nothing to be gained, but lots of link juice recirculation within the site to be lost. You definitely want that link juice to circulate up vertically to the next higher category... maybe not across categories... but definitely up and down.
Suppose you have a category called Iron Widgets. And in that category you had several individual products, like 15 Inch Tall Iron Widget, or Japanese Forged Iron Widget, and stuff like that.
And due to the fact that their isn't a HUGE difference between one widget and another, the description of each widget product page kind of overlaps with the description of all the other widget product pages.
It may be that the issue is that these pages are targeting nuances that aren't really distinguished in most searches, and that they are perhaps better left to an order form or a product sub-page.
It occurs that some thoughts I just posted in a different discussion about whether or not to combine product characteristics under one url, might have bearing on this discussion here....
Dynamic Single Product Page - Can this be successful for SEO?
In the above thread, I was basically arguing against combining too many diverse product categories into one dynamic page. In the course of explaining what I wouldn't combine, I also described what I would combine. Note that these considerations aren't restricted to dynamic pages. I'm suggesting the use of form option values to specify different shirt sizes, eg. Why not also for different heights of iron widgets?
...if you were targeting, eg, a particular piece of clothing, like a shirt, you might be able to manage to include characteristics like color, size, and pattern all on one page without skewing the search targeting. These are characteristics I wouldn't normally try to target on separate pages anyway. I'd normally leave these choices to the option values in the ordering interface. The lists of colors, sizes, and patterns that would appear in your source html would in fact be expected.
The dilemma comes if your "15 Inch Tall Iron Widget" and your "Japanese Forged Iron Widget" differ in much more than height... and I suspect they do. Then they are basically different products, and they do require different pages. I think you then really need to strain to uncover and emphasize differences between them that are likely to show up in a search query, and to reflect those differences in your product descriptions, which should describe the features of the product, why the customer might choose it over another, and where and how the customer might want to use it.. briefly, but beyond simply product specs.
I should add, btw, that I know of many site owners who are straining like crazy to rank for their category level pages rather than for their product level pages, because the number of searches is much greater for the category level. I mean, do people really search for [15 inch tall iron widgets]? Is that traffic you're really expecting?
At issue here, if you can settle for category level rankings, is to enhance those category level pages... making sure your navigation on the category level pages is laid out in such a way that the choices are more easily navigated and the product choices are prominent and readily seen. Many shopping carts, eg, lay out the products in checkerboard patterns, which I feel is a user-unfriendly display. There's no place for the eye to settle.
Perhaps you'd have better luck with a list format, resembling a serps page, eg, with product thumbnails at the left of each text listing that would run in one or two or three lines across the page. This compresses the listings vertically, and simply scrolling down the page exposes each product in sequence much more clearly. The thumbnails on the left, in a column, hold your eye. Scrolling down the list is almost like navigating a mobile app. There are ways to provide separation that are attractive. If you do this, list most popular products, or the ones you want to sell the most, at the top of the list.