Some of the pages are returning `page not found` errors

Selected answers from the Dumb SEO Questions G+ community.

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  Michael Martinez: It`s doubtful these pages would have a negative effect. Negative in what way? Bing and Google don`t punish sites for publishing content. If they are being found, however, then the search engines are following links to them. You could block the pages in "robots.txt". But before you do anything, you should determine if people ARE landing on them from search. If so, where do they go from there? Don`t make assumptions. Get the data and then decide what to do.
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  Stockbridge Truslow: I would say that the testimonials archives and individual testimonials are likely useless. That can vary too. If they have star ratings and they are tied into a service page, then you have to work it a bit differently. Author pages are potentially useless, though if you have a specific user tied into their G+, Facebook, and other accounts, then indexing that author could be useful. It depends if that author has any real authority factor (or if you`re trying to establish authority/credibility for them), I suppose. If it is an author with some authority and it`s a republication or whatever - it`s probably not that useful either. Author pages are a bit tricky to handle. They can help, but they need to be done right to do so. Blog Category Archive pages, I`d DEFINITELY leave in the index. They give context to the article based upon subject.