... as long as they are related to MySQL or database topics.
Unfortunately, there were often comments on my articles that were just spam and they had nothing to do with MySQL or databases at all. I always deleted them manually and one day I decided to only allow comments to people who are logged in.
But I received quite a lot of feedback from people who wanted to post relevant comments, but they didn't have an account and so couldn't answer. Now I have changed the setting back to its original state, because I'm quite curious about what people think about what I write and so, they should have a chance to tell me and the blog's readers :-).