The plural first person pronoun (we) is a bit different from its singular counterpart. Not only in number, I mean. The three-person system is pretty straightforward in the singular. I refers to the one who speaks ('first person'), you refers to the one spoken to ('second person'), and he or she is someone outside of the conversation ('third person').
The three persons in grammar
However, when someone says we, there aren't suddenly two speakers. There is still just one speaker, who considers him or herself part of a group of people. But who is in that group of people? Who's we? An import question, because it might include you! And when someone says "we will take the blame", "we are going to Disneyland", or "we will clean up the mess", you may find it an important nuance; you may not feel like taking the blame, or cleaning up the mess — Disneyland, on the other hand, sounds fun.
In English, there's only context to find out if you are we. What? But some languages actually use different pronouns to avoid any confusion. In Indonesian, for example, if you hear kita, it would mean you're expected to help cleaning up the mess, if you hear kami, it will kindly be done for you. In linguistics, this is called inclusive and exclusive 'we', and it's a really useful feature of language if you ask me.
Unfortunately, not that many languages have it, though. It is a feature mainly found in Oceania. Maybe the Aussies and Kiwis can get something going to introduce it into English?