The time to index is certainly dependent on their size, but I don't see how this sort of a/b tests on SEO wouldn't work on other sites. The sample size of page

The time to index is certainly dependent on their size, but I don't see how this sort of a/b tests on SEO wouldn't work on other sites. The sample size of pages they have to play with, and the fact that they get indexed within a couple of days does make it all the more viable though.