
Knowing what your readers think about your website, what they like or dislike about your site, bugs, spelling mistakes, missing images, broken links etc. is incredibly useful and important. There are many services and ways to gather feedback.

Kampyle
I will start with my favorite one, that I myself use, Kampyle. It is different from all of the other services in that does not only do a great job at gathering feedback but it also analyzes the feedback it in order for you to take action. In fact, Kampyle collects, analyzes and manages your website visitors’ feedback.
You can use it out of the box or customize the look and feel. The installation takes just a few minutes and is very simple to add on your site. The management application includes tons ofactionable reports that will help you quickly understand what has to be improved and what are your users saying, even without needing to read each and every specific feedback item.

Pros: Easy to install and customize. Great analytics. Users are not taken away from your site.Feedback is visible only to you. Free version.
Cons: You have to upgrade to the paying version to get Google Analytics integration.
Forums
You can use forums such as Young Entrepreneur, Blogcatalog, Site Point or Web Developer which all have site and blog review sections.
Pros: You can reach a large group of people.
Cons: One time only, way to get feedback.
Create a page
An easy way to receive feedback on your blog or site is to create a feedback page and have a contact form with: suggestions, bugs and feedback.
Pros: People will continuously provide feedback.
Cons: Takes up valuable site space.Can generate up to ten times less feedback because most people don’t have the time to fill out all of their information.
Email Request
If you want a one time feedback deal just shoot out an email to friends, family and connections asking them to do a favor and take a few minutes to check out your site and jot down problems.
Pros: More personal.
Cons: One time way to get feedback. It’s risky to ask feedback from people who are not your users. They may have great ideas, but as they don’t really know your site or blog, their ideas and suggestions might be not relevant and drive your real users away from your blog or website.
Social Media
Another method is to send out a message through social networks such Facebook, Twitter or others asking for feedback.
Pros: The use of social media could broaden your request.
Cons: People could think you are just self promoting. You might get lots of feedback and it will be hard to manage it, prioritize it, and see the full picture of what should be done.