what is debug mode ?

[zodehala]

i add this to config.php to enter into debug mode:

$config['Misc']['debug'] = 1; 

1. what is debug mode ?
2. what happening ?
3. when do i use debug mode ?
4. who can use debug mode ?
5. whic spesification donot i use in debug mode ?

[Jake Bunce]

Debug mode is mostly for development purposes. It allows you to add and remove settings in the Admin CP, view load stats on the forum pages, and change things you otherwise wouldn't be able to change.