Email/mailing list version:
Know anyone in or around San Francisco who's been curious about their family history? I am looking for participants for a paid research study I am conducting for [company]. We are looking for people in the SF Bay Area who are getting started researching their family history, or who are very interested in doing this. we will visit selected participants at home to talk about family history research for 90 minutes, and they will be paid [incentive type and amount]. To be considered for the study, please follow this link and fill out the screening survey: [screener URL]

Facebook ad versions:

Are you beginning to learn about your family history? Always wanted to know more? Live in the SF Bay Area? You could earn $125 for participating in a paid research study with [company]. Go to [screener URL] 

Know someone in the SF Bay Area who's just getting into genealogy and their family history? They could earn $125 for participating in a paid research study with [company]. Send them to [screener URL]

Twitter version:

Curious about where u came from? [Company] seeks SFBayArea folks new 2 #familyhistory 4 a paid ($125) study: [screener URL]