I think Digital Web is an example that handles this issue well. They do not accept shareware, demos, etc. it has for review. They review books but they do not promise to ship the book back. I know this information going in so that I can somewhat make an informed decision.

What I think should be disclosed (which often is not) is when a reviewer is reviewing a product of a friend’s product. For example, if someone I know personally wrote a book and I reviewed it. There has to be a bias there and I think that should be disclosed, even though there isn’t money involved. I’ve seen it happen many times where a reviewer did this and once it came out that the reviewer and the author were friends, the entire review lost its weight, meaning it hurt the author in the long run.

Of course there are somethings that are none of our business as consumers but that’s another post entirely.