twitter for journalists
One of the things that makes Twitter such a powerful "news amplification" medium is the concept of the "retweet," which is essentially a way of repeating something someone else said (with or without modification), extending its message out from the originator's network to your own network.
Twitter's users - not Twitter itself - invented the retweet and made it part of Twitter culture. A traditional retweet starts with this syntax:
An old-style retweet starts with the syntax
RT @username, which of course cuts into the 140-character limit. The text is modifiable before posting.
In this style of retweet, you have the opportunity to modify the text, either to add additional commentary or to shorten so it fits in the 140-character limit. Note that some users will mark a modified retweet with the letters "MT" rather than "RT."
Twitter later embraced the concept of the retweet officially, and baked it into the service. In an "official" retweet, the length of the tweet is not affected by giving credit to the originator. Instead, the Twitter client will mark the retweet, either by overlaying the retweeter's icon on top of the originator's icon, or by referring to the originator below the tweet.
In a new style retweet, the message cannot be modified. Credit is given with text below the tweet, or by overlaying one icon over the other.
In the example above, we do not follow @ericuman, but we do follow @poynter. This tweet still shows up in our stream because @poynter deemed the message worthy of amplification.
Unfortunately, an official-style retweet cannot be modified, and you cannot change the "from" account (i.e. you can't retweet a post that came in through one account out through another).
Both styles have their advantages and disadvantages.