Project description:Since 2014, the Society of Critical Care Medicine has encouraged "live-tweeting" through the use of specific hashtags at each annual Critical Care Congress. We describe how the digital footprint of the Society of Critical Care Medicine Congress on Twitter has evolved at a time when social media use at conferences is becoming increasingly popular.DesignWe used Symplur Signals (Symplur LLC, Pasadena, CA) to track all tweets containing the Society of Critical Care Medicine Congress hashtag for each annual meeting between 2014 and 2020. We collected data on the number of tweets, tweet characteristics, and impressions (i.e., potential views) for each year and data on the characteristics of the top 100 most actively tweeting users of that Congress.SettingTwitter.SubjectsUsers tweeting with the Critical Care Congress hashtag.InterventionsNot applicable.Measurements and main resultsThe Critical Care Congress digital footprint grew substantially from 2014 to 2020. The 2014 Critical Care Congress included 1,629 tweets by 266 users, compared with 29,657 tweets by 3,551 participants in 2020; average hourly tweets increased from 9.7 to 177. The percentage of tweets with mentions of other users and tweets with visual media increased. Users attending the conference were significantly more likely to compose original tweets, whereas those tweeting from afar were more likely to retweet Critical Care Congress content. There was a yearly increase in content-specific hashtags used in conjunction with Critical Care Congress hashtags (n = 429 in 2014 to n = 22,272 in 2020), most commonly related to pediatrics (18% of all hashtags), mobility/rehab (9%), sepsis (7%) social media (6%), and ICU burnout (1%).ConclusionsThere has been significant growth in live-tweeting at the Critical Care Congress, along with the increased use of content-specific hashtags and visual media. This digital footprint is largely driven by a proportion of highly engaged users. As medical conferences transition to completely or partially online platforms, understanding of the digital footprint is crucial for success.