We had an issue yesterday that has caused some Tweets to not be displayed. This issue has been resolved, and affected Tweets, along with the favorites and retweets on those Tweets, have been restored. http://status.twitter.com/post/80718245447/tweet-display-issue
This issue also caused status deletion notices to be sent thru our streams. To prevent data loss in your own Tweet store that might be occur following these false deletion notices, we will be republishing these tweets today, with the original created_at date and current favourites_count and retweet_count. This is for all stream types.