Lordfly is basically correct, but if that was all Twitter had to offer, I would really have no use for it.
Here is what I like...
1) The Twitter page is very simple. So, it can be used effectively on cell phones, kindle readers and other mobile devices.
2) Twitter users often identify events or issues with a tag [Examples: #monroe or #mcf - for Monroe County Fair]. If a person types that tag or a keyword into the search function, it will show in real time other tweets on that subject. I have been at public meetings where several people tweet and it is really neat to have a record of the meeting from three or four different perspectives. It also allows the tweeters to chat with one another.
3) Users also use "RT" to note "Recommended Tweets." There are ways to access these recommended tweets.
4) Twitter also seems to allow for outside programmers to create functions for Twitter that don't really appear in the more closed Facebook. So, this allows a user to dump feeds into Twitter. And once dumped into the system, these feeds are opened to the Twitter search function.