text_1: As millions vape, e-cigarette researchers count puffs, scour Facebook.
text_2: One team of researchers assessing the risks of electronic cigarettes is counting the puffs taken by volunteer “vapers.” Another will comb Facebook for posts on how people are tinkering with e-cigarettes to make the devices deliver extra nicotine. A third is building a virtual convenience store for 13-to-17-year-olds, measuring how e-cigarette displays and price promotions influence whether minors buy the increasingly popular devices.