Why do websites generate random alphanumeric strin

Question

Why does many sites (youtube is good example) generate string of random number and letter instead of using for example the row id?

usually its something likes this

bla?v=wli4l73Chc0

instead of like

bla?id=83934

Is it just to keep it short if you have many rows? Or is there other good things about this? Because i can imagine: bla?id=23934234234 dont look so nice

Thanks and cheers

Answer 1

Some environments also use this to establish state variables for the session. For example, if you have an ASP.Net app that is using cookieless sessions, you'll find a similar code in the URL.