They've been around for a while now, I think lately they've been growing personality due to their BL titles (the sequel to King's Maker being a major one among others) and their shoujo romance isekai light novel adaptations. They're a bit different than Lezhin which is the same publisher both local in Korea and overseas, while Tappytoon mainly gets the English rights to webtoons from Korean publishers like Daum or the like. Also, these rights often are only exclusive to a single publisher for a limited amount of time, which is why you might notice the same work published on both Tappytoon and Lezhin for example. Though I might be wrong on how it works.