Also very old site. High authority. Thriving community. Lots of backlinks. Exact match domain.
We got his with the unholy trinity of updates lately...
UGC hit - since we have a community with forums and other resources.
Exact Match Domain hit - Exact as they come. Hit hard on some search terms.
Amazon and big box pushed to top of serps - Serp de Jour is big box with amazon being the major beneficiary.
Again, this has been ongoing for quite some time.