Anything created on the forums, user icons, pictures, user account, post, etc. can all take up disk space on Computer Hope. However, the actual posts and accounts are as Dairyman mentioned small. However, in large quantities it can consume a lot of disk space, which is why every once in a while I'll delete old user accounts (e.g. accounts that haven't been used for several years). However, no post (unless forum violation or user deletes it) is deleted.