Jon Harrop often comes across as too negative and is described as "well known internet troll". However, his thoughts are usually quite valuable and often better than what he is credited for. His contributions to the F# community are well known.

The Lisp community remembers when he trolled them. Basically he wanted to create clicks for his commercial offerings, unrelated to Lisp. Some kind of anti-marketing strategy, which fired back. Since then his business failed and he trolls the Haskell community as a hobby, from time to time.

Really 'valuable' thoughts from him are rare. 'Valuable' more for him. ;-)