Techcrunch reports that Twitter has implemented a new anti-spam feature that blocks duplicate tweets (with exactly the same text) in any 24 hour period.

If you try to enter text for a tweet that is exactly the same as a tweet you’ve recently sent, it will block it, saying “duplicate text” in a white drop down overlay (pictured below). It would appear that there is a time window for this, and it may be 24-hours. I tried copying-and-pasting two tweets that I sent a few hours ago, and those were both blocked. But then I tried one from two days ago, and it went through.

Now this is not entirely a bad thing, in my view, but it will require people like me, who try to reach followers at different times of day, to modify the tweet before resending. I'd prefer an opt-in system by users who don't mind getting my duplicates, but that would require far more architecture than Twitter's Tinker toy system can support right now. As for whether this impacts Retweets, I can't see how it couldn't.  The Twitter system doesn't know anything about the "RT" signal, nor care.  It's just more text, so if you're in the habit of copying and pasting a retweet, these too will need minor edits to make each tweet a bit different.. Read the story details..