Not me, but a "startup" I'm consulting for today that's pivoted many times over the last 13 years. They spun out a different website focused on a single offering about a year and a half ago that led to them developing a focus (sales and tech both) on a specific market and has led to a crazy uptick in business. I can share the URLs if the HN community is curious to see the difference between the two.

Editing to include URLs: - Original site: www.devhub.com - Spin-off: www.rallymind.com