Are Sponsored Reviews and Paid Blog Posts Evil?

Quite a hot topic.

My short answer would be that sponsored reviews and paid blog posts are not good or evil per se. It all depends on the context.

The first factor you need to have to make sure sponsored posts will not backfire on you is transparency. This means that you should disclose what is paid and what is editorial content on your blog. If readers can differentiate those clearly, they won’t lose trust.

The second factor is relevancy. It would be weird if you accepted sponsored reviews of financial products on your technology website. Readers would notice this as well, and many of them would get annoyed.
Finally, it is important to have moderation. In other words, the bulk of the content on your website should be editorial content. If you start running as many sponsored posts as editorial ones your readers will leave pretty soon.

Every site is different, though, so make sure to evaluate your own situation before proceeding one way or the other. For instance, you could experiment with one sponsored post and evaluate how your readers will react, ask them some questions about it and so on.