What does the /b/ mean in the URL of Fclose.com – SysTutorials QA

There is a ‘/b/’ in the posts’ URLs on fclose.com . What does it mean?

It originally means “blog” when the blogs are first set up. This site changes to not only a blog (one good example is this forum) over time. However, the URLs are kept unchanged and the ‘/b/’ has no special meanings anymore.