There seems to be two different discussions going in this thread. Frequent-flyer programs don't require to do any of reading blogs, watching YouTube or whatever

There seems to be two different discussions going in this thread. Frequent-flyer programs don't require to do any of reading blogs, watching YouTube or whatever. You just input your number at booking time (or later if you forgot or someone else booked for you). That's literally all there is to it. After a number of flights this gives you extra baggage allowance and line skipping and preferred treatment.