What does it mean to jailbreak your iPod touch?

I might be getting an iPod Touch eventually, but the price is pretty steep. Anyways, I've seen people on youtube posting vids showing you how to "jailbreak" your touch, but what does it really mean???? Is it necessary????

I've seen alot questions about jailbreaking an ipod touch or an iphone. What does that mean??? I'm getting an ipod touch soon, so please help me.

Im getting the new ipod touch for xmas and was wondering what it meant to jailbreak an ipod. Is it worth it, and does it affect any guarantees or anything? thanks

I own a 16 gb ipod touch and i was wondering what jail breaking it does? Is it illegal? Also, my ipod touch wont play some youtube videos for some reason, even though ive watched them before. Would it help with that?

everyones talking about how great their ipods are after jailbreaking them, so i want to jail break mine and how do you do it, and what does it mean like what will be different about it after?

Is it safe to do? What does it enable my ipod to do? And would I be able to do it with my ipod touch gen 1 8 Gigabyte. ?

I've seen so many questions about jailbreaking an iPod but was does it mean. Sorry I'm lost I just got my iPod lol.

I have a ipod 3th gen, 8 gb,,!! can u do it whit this ipod,,?!?! and how to do it,,?!?! thnxx,,!!

I have heard of jailbreaking, but I dont know what it means