Newsletters, like podcasts, are an old technology that is going through a renaissance. This renewed interest in email newsletters has its roots in big shifts happening in technology, consumer habits, and economics. The facts and statistics below highlight how quickly email newsletters are growing and provide a glimpse of how they are being used.

The Solo Newsletter

In her “Back to the Future” report on newsletters, Charlotte Fagerlund discusses Rusty Forster’s Today in Tabs, which started as a personal project and was eventually bought by Newsweek. He’s not alone. Many journalists are using personal newsletters as on-ramps into other news organizations or as stand-alone projects. Philip Balboni, the founder GlobalPost (which he sold to WGBH), is launching a new newsletter on international reporting. Nick Quah left his job at Slate to turn his newsletter about podcasting into a business.

Meeting Millennials Where They Are

Email is proving to be a hugely popular medium for reaching younger audiences. Started by two former NBC journalists, theSkimm was launched as a curated newsletter of headlines for millennials. As of August 2015, it had 1.5 million subscribers. Lena Dunham’s Lenny Letter currently reaches more than 400,000 subscribers. According to Fagerlund, Mic’s newsletter Mic Check, started in May 2015, boasts over 80,000 subscribers. When Clover launched, it had 1,000 sign ups on day one.

How Are Newsletters Being Used?

Quartz launched its newsletter alongside its website, and the newsletter informed the eventual design of the homepage. The Quartz newsletter now has about 150,000 subscribers (see the Quartz case studies in the reading list at the end of this guide). The BuzzFeed News email newsletter served as a prototype for their eventual news app, and the two still share a similar look and feel. Leonard Bogdonoff notes that in 2015 BuzzFeed reported a 23 percent month-over-month rate of growth on traffic-to-site generated from newsletters. “Visitors from newsletters are some of the most engaged readers spending 3 minutes longer on the site than other channels,” Dan Oshinsky, Director of Newsletters at BuzzFeed, told Bogdonoff. The New York Times, which used email to send updates to readers during the Paris terror attacks in 2015, has experimented with other short-term email strategies alongside ongoing newsletters.

How Many Newsletters Are There?

As of last year, TinyLetter — one of many newsletter services — had more than “161,000 users creating newsletters and more than 14 million subscribers to those newsletters.” Fagerlund writes in her report that in November 2015 The Washington Post boasted 61 different newsletters. The Wall Street Journal had 43 and a number of email breaking-news alerts. The Financial Times had 40 different newsletters. The New York Times had 33, Forbes had 30, The Daily Telegraph had 29, and The Guardian had 26.