The 280-character spike

The length distribution of tweets has shifted in response to raised character limits, but it's still the case that a disproportionate number of tweets use all the characters they're given.

The distribution of tweet lengths in a 2019 dataset

A sample of tweets gathered in 2019Twitter stream 2019-05. Internet Archive. (2019-10-27). still exhibit a telltale spike approaching the character limit, but it is smaller than the tweet distribution from a decade earlier. The peak of the curve has also shifted leftwards, to 15 characters, due to a separate change in 2016 that excluded media attachments and certain at-mentions from the character count.

The most interesting feature of the above graph is unfortunately an artifact of the dataset — the massive spike at 105 characters can be blamed on a spambot network broadcasting identical copies of the same tweet when the dataset was collected.