Kahoot launched a paid service yesterday. You might have seen some Tweets or Facebook posts about it and gotten concerned as did the folks who emailed me about it yesterday. The paid plan isn't going to have a direct impact on your teacher account.
The new Kahoot Plus plan is designed for corporate users who want to have their own branding on a game, who need a secured peer-to-peer sharing environment, and need advanced reporting options designed for business environments. In other words, not things that teachers generally request.
In the announcement that Kahoot made yesterday, the company reiterated its commitment to keeping the platform free and open to teachers and students. The announcement made it seem that the company hopes that Kahoot Plus accounts purchased by businesses will help with the goal of keeping Kahoot free for schools.
And in case you missed the announcement in September, Kahoot's mobile app now supports distributing games for students to play at home. Check it out.