Depends on each company... I played WoW in beta for a bit, and most of it was "play wherever you want, except these zones are off limits. Let us know of any bugs, kthxbye"... Whereas other games I've played in beta were "Please stick with us and attack this one mob. We are going to try and break it." or "Please do as many of the quests in this zone as possible. Please let us know of any spelling or grammatical errors, as well as odd issues such as an NPC not resuming a conversation if you close their text window during the quest giving process." etc etc.
It's fun and exciting and you get to play... stop, /report or /bug, and play some more.
I love finding bugs, gives me a sense of pride in a game that is stable and runs well.
~ Jaraeth