Which sites enabled Resource Timing?

Analysis
1 
SELECT domain(url) as domainname, count(*) as num
FROM [httparchive:runs.latest_requests]
WHERE lower(respOtherHeaders) contains "timing-allow-origin" 
GROUP BY domainname 
ORDER BY num desc

Relevant part of the spec: http://www.w3.org/TR/resource-timing/#cross-origin-resources

2

Sadly, basically nobody… as of mid 2013:

3

Wow, was totally not expecting that, is the header actually ratified now?

4

Yup, ResourceTiming is implemented in IE10+ and Chrome! Andy Davies did a nice writeup on it in WebPerf calendar: http://calendar.perfplanet.com/2012/an-introduction-to-the-resource-timing-api/