BuddyPress.org

It’s going to be more complicated to save items into wp_usermeta (which is I assume what you’re doing, given the link) with update_user_meta() from the BP profile page. You’ll have to hook a function to somewhere in the BP loading process that will catch the value of $_POST and manipulate the data manually.

Can I ask what might be a silly question? Why don’t you just use BP profile fields? Dashboard > BuddyPress > Profile Field Setup. That’ll add new fields to the profile that can be displayed and updated natively through BuddyPress.