Table 2:

Social Media Use Characteristics

Frequency of social media platforms and role among n = 120 studies.

		Number of Studies n (%)*
Social media platform(s) used
	Facebook	59 (49.1%)
	Twitter	28 (23.3%)
	Specific rare disease website or form	19 (15.8%)
	Unspecified “online support group”	13 (10.8%)
	Unspecified “social media”	13 (10.8%)
	PatientsLikeMe	6 (5.0%)
	YouTube	4 (3.3%)
	Instagram	2 (1.7%)
	Reddit	2 (1.7%)
	Other**	7 (5.8%)
Role(s) of social media
	Recruitment	79 (65.8%)
	Primary data collection	64 (53.3%)
	Secondary data analysis	38 (31.7%)
	Intervention deliveiy	4 (3.2%)
	Other	1 (0.8%)

^*Categories are not mutually exclusive, percentages may sum to >100.

^**Social media sites included in “Other” were all used by one study. These included: Pinterest, WeChat, Tumblr, LinkedIn, RareConnect, Yahoo, and “internet based blogs”