twitter.com allows you to delete a tweet through the web api, but it still remains in the search cache. When tapatio collects tweets it does so via the search api and will pick up even deleted tweets. This may not be a problem, but it may result in collected information that is not relevant to us. It seems that some people are using this as a method of editing a tweet, so you may get two similar tweets. Consider the two posts around 7:53 and 8:54 from the following: http://tinyurl.com/q2sjok.