Yep, I recall that the FB like buttons proliferating the web was perceived as a huge threat (and drove the +1 buttons.)

> Google had wave, blogger, orkut and other things. It's not like they didn't test different things or try to emulate others. They just failed.

Wave failed, but was a fantastic experiment, and the learnings went into Google Docs/Sheets for collaborative editing.

Blogger and Orkut didn't fail. They were hugely successful -- Blogger worldwide, and Orkut primarily in Brazil (and India, I think.) Both had great rides, and withered away as everything does.