(note: ask ten people the name of these features, and you might get ten answers...)

Sub-Ratings

Sub-ratings are any rating that is not an overall rating. Often, when it comes to product reviews, sub-ratings are generic in nature, such as value or quality. But they need not be. For example, a laptop can be rated on attributes such as display or keyboard or battery life. (see: notebook computers at Circuit City)

Sub-rating information is often aggregated at the product level, but rarely makes its way to the category level. In other words, you can see this information after you are already viewing a product, but you cannot use this information to get from the category level to the product level.

If a product category only has one type of rating (overall), it can be used as a sort option. But what if a product has several types of sub-ratings? In that case, perhaps sub-ratings could act as product attributes, the way digital cameras have attributes like megapixels and optical zoom, and be manipulated in the same ways.

Sub-Reviews

Sub-reviews are short summaries that have more structure than the main body of a review.
(see: a laptop review at Epinions, includes Pro, Con and The Bottom Line)

By far, the most common of these is the summary. A bit less common, but oh so useful, are pro and con. When used on a page of review summaries, Pro and Con can offer a quick, well-rounded product overview. Also, they can help determine which reviews to read in full, by giving us a glimpse of a reviewer's balance, or lack thereof.

I would love to see more adoption of Pro and Con.

And I am more than a little surprised they are not included in a microformat such as hReview, quite frankly.

oops, time is up, the weekend beckons, more later...