How do you collect feedback for your blog posts? (for technical blogs, documentation, how-to's, etc.)

Google Analytics gives you the metrics to see if your articles are popular, but how do you guys gather more precise feedback about your blog articles, landing pages, etc.?

I wonder because I don't only want to know if people find my articles helpful, but also what they liked and disliked about them.

On articles for technical documentation, I found that there's usually some way of giving feedback at the end (see this page for example - you need to scroll to the end).

If you click on like or dislike, a window pops up, asking what you liked/disliked about the article.

My questions here are:

Are you using some kind of widget for gathering feedback? If yes, which?

If not, how do you gather feedback?

Would you care about a widget that allows you to collect feedback?

Would you be willing to pay $10/month for a product that offers something like that?

I'm looking forward to what you all think about the topic!

Since I'm a programmer myself, I wanted to create a widget for myself and maybe make it public if there's more interest.