It's not about when the company was founded, it's about the release of Squarespace 6, which compares favorably to WordPress.com's current incarnation.
I enjoy learning the bootstrapped rags to riches story about Squarespace, but your title frames the story as if its about a new competitor to Wordpress the open source CMS, and it is not.
It's a nice proprietary option (maybe even and exceptional one) but the article byline is still very linkbait.
I am unapologetically from a view where that kind of PT Barnum grade nonsense didn't square well with real journalism. I still cringe at it.