The Boston Globe’s health and medicine site Stat is the latest to roll out a membership program in the hunt for a model to fund online journalism. For $299 a year, subscribers to Stat Plus will get exclusive content about pharma and biotech news, a private Slack channel and exclusive events invites, among other benefits. It may be ambitious for a year-old publication to launch a membership model, but Stat says it saw an opportunity to charge given the market is growing and not yet saturated by media coverage.