We later found that this was because attack tweets were generally very recent, created within five minutes before the target keyword becomes trending (See $5.2.3). Ratio of Deleted Tweets to All Tweets Posted Before Trending Attacked 10,000 False True 267 1,000 7,239 100 296 198 164 131 1,166 14 158 10 116 89 26 35 21 10 12 11 6 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 Figure 6. The histogram depicting the ratio of all tweets that are created and deleted to all tweets created before the trend enters the list. This ratio is overwhelmingly high for attacked trends while it is zero for the majority of non-attacked trends. Number of Trends