I run a news-oriented website, and all content is shared on Twitter.
In recent months, I have noticed that several accounts are stealing the information - be it facts or pictures from the Tweets - without any form of attribution
These accounts position themselves as "Twitter news sources" and target the same audiences, so they are actually directly competitive. They are also limiting the exposure of my original Tweets, which has a deleterious impact on link-traffic to my original site -- and thus revenue.
What makes it worse is that my account, for whatever reason, has not been verified by Twitter - so the lay person is not going to automatically assume that the material originated on my site. This hurts with branding and professional credibility.