In the good old days, you could earn Twitter karma from reposting someone else's tweet under your own handle. If you've ever practiced this once socially acceptable charade, the jig is up.
According to TheVerge, Twitter is now intellectual-property-friendly, giving clever quipsters their due credit. If you spot your pun, joke, or one liner under someone else's handle, it's well within your rights to report it. Not that it wasn't within you rights before, as copyright kicks in the moment you write something, but Twitter is responding to the complaints with deletions.