Review of Can I use... powered by the Slant community.
Browser support tables for HTML and CSS.
Ranked in these QuestionsQuestion Ranking
Pros
Pro Supplies usage data for all countries
Pro Provides good list of resources
When serching for a feature you typically find a nice list of really valuable resources, such as spec on w3c website, and blog posts desribing usage in details.
Cons
Con Not that good for learning
It's a super cool catalogue for people who know what they are doing, just to check if their tricks apply to certain use case or project. It doesn't serve as a good starting point nor roadmap for css newbies.