Inside: The 300k-Subscriber Newsletter Built by Jason Calacanis

nside is a company founded by Jason Calacanis, an early Uber investor. For each vertical niche with over 2,000 subscribers, they assign a writer who produces original content or curates and shares articles from that field, sending regular newsletters to subscribers.
It now boasts over 300,000 subscribers and an average email open rate of 40%—impressive, especially compared to WeChat public accounts, which average less than 3%.
Revenue model: free users see ads, while paid subscribers get an ad-free experience plus exclusive content.