>What is lounge if not a textboard?
A bulletin board; or more specifically, a thread-float bulletin board. I wouldn't go as far as saying it's a 2ch-type board since it's not an exact replica of 2ch's system - but then neither are most Japanese bulletin boards besides a handful of direct 2ch/5ch spinoffs and clones. At the very least, kokonotsuba has most of the core 2ch features: nameless posting, age/sage, tripcodes, capcodes, etc., as well as other features like the thread list

"Textboard" started being thrown around colloquially around 2007 to describe 4chan's former discussion boards, as a way to distinguish them from the imageboards. It's not a term the Japanese ever used themselves, nor is it really accurate to describe 2ch/5ch and 2ch-type boards this way - not least because many of them do in fact support images and other media