What is the mean of "Subscribe to this topic"

1) I am sorry for my poor undertanding. I want to know the meaning/usage of "Subscribe to this topic" check box.

2) What does it means "BBCode: on"


if you subscribe you will receive email of newer posts.

bbcode is and alternative to html and used for forums. it is used for formatting etc.

Subscribing means a truck load of emails in you Inbox whenever someone replys on that subscribed thread, and can have endless fun deleting those emails them aswell.

BBCode is all the fancy stuff, like making your text bold, italics, underlined and all the emoticons e.t.c