I’ve never thought about running my own blog until I came across “Daj się poznać” contest. The main point of the event is to make programmers realize that blogging can be enjoyable and very beneficial activity.
For me it is a great way to archive projects’ development process. Sure you can store your code in repository and dig into it some time in the future. It is however certain that you will forget some (most?) of the concepts that were in your head during development. Blogging is a great way to preserve that concepts. There is also a slight chance that other people might read your stuff and learn something. How many times have you struggled on some complex problem until you found that one awesome post on someone’s blog? I’ve been there many times.
There are just so many benefits of blogging, so why should one not do it?