New top story on Hacker News: Ask HN: Which startups have the most interesting pivot stories?

Ask HN: Which startups have the most interesting pivot stories?
16 by jd_illa | 6 comments on Hacker News.
Someone on HN said Notion started as a research tool. Couldn't find info on that online, but it got me interested in thinking about unusual/interesting pivots. I've read about some of the big ones (Odeo --> Twitter, Tote --> Pinterest), but curious if anyone has more recent or lesser known ones.