Here are a few tips you should consider concerning blogs and leaving comments;
Do not post another writer’s work in your blog. Link instead. Some blog authors require a certain number of hits to their page in order to glean some income from their work. Cutting and pasting those words steals hits from them! There is also to consider the copyrights all writers have to their work, which includes email and web site. If its printed somewhere, its copyrighted. I also link with direct credit, to let readers know who is responsible for the article.
Add to your blogroll web sites that link to you. I do not add links from other wordpress blogs that have ‘produced links’ automated in the blog. If they went through the trouble to link to me, and their blog/site includes the same topic as mine, I link them.
Don’t leave comments just so you can leave a link back to your site. Such action is tacky. Instead, leave some comment about the blog or blog post, and only then add your link. Keep in mind, that many times a comment already links back to your blog anyway.
Don’t feel obligated to keep all comments. If some visitors leave spamlike comments, overly critical, or just negative comments, you are entitled to delete as necessary.
Try to leave comments on blogs you appreciate. Even a simple comment helps the author that their blog is being read and enjoyed.
Don’t forget to subscribe to blogs you really enjoy. This is with the RSS feed that most online journals provide. You can find them by clicking on the RSS link or finding the RSS icon.
Link the blog or blog post to networking sites to help encourage readers to the author’s site. This enables more readers to find the content through sites such as Digg, Twitter, or StumbleUpon.