Yes. Commenting on YouTube is free. All you have to do is having an account.

In computers, "commenting the defaults" probably refers to commenting out the default settings in a configuration file. Commenting out the defaults will preserve them for reference when you want to change them, but will stop the program from reading them and will instead use your own settings. Commenting varies by program, but the most common commenting is to either use a pound symbol (#) or two forward slashes (//) at the beginning of each line.

Something called commenting.

To follow the nature as it is without translating or commenting or contradicting.

Fox Sports have changed sport commenting in many different ways. The Fox Sports commentators have better sound and can commentate better with better skills at it.