Using Twitter to Learn about the Autism Community 17 the content of the tweet which contains them. Recall from Section 4.1 that 2,260,284 or approximately 25% of the collected tweets contain hashtags. (a) ASD hashtags ‘word-cloud’ (b) Control hashtags ‘word-cloud’ Fig. 6: The most frequent hashtags in the (a) ASD and (b) control data sets, shown as so- called ‘word-clouds’. The font size used to display a particular word is proportional to the corresponding word’s frequency in the data set. Note that the hashtags corresponding to the search keywords have been removed before producing the ASD word-cloud.