After todays various affected major websites you might ask who is actually also affected together with the well known sites as Amazon, Twitter or Github.
Using the results of a monthly scan I automatically run on the top 500 Alexa sites it is easy to find out. The only thing you need to know is that the Dyn DNS server domain is dynect.net (detailed results).
Top Affected Sites
6pm.com about.com adcash.com addthis.com amazon.ca amazon.cn amazon.co.jp amazon.co.uk amazon.com amazon.de amazon.es amazon.fr amazon.in amazon.it answers.com bitly.com businessinsider.com chase.com chip.de disqus.com ebay.co.uk ebay.com ebay.com.au ebay.de ebay.in ebay.it etsy.com evernote.com exoclick.com github.com github.io goodreads.com hostgator.com huffingtonpost.com imdb.com indeed.com indiatimes.com jmpdirect01.com moz.com nytimes.com outbrain.com overstock.com pandora.com paypal.com photobucket.com pornhub.com quora.com redtube.com scribd.com shutterstock.com soundcloud.com speedtest.net stumbleupon.com t.co theguardian.com theverge.com tripadvisor.com trovi.com tube8.com tumblr.com twimg.com twitch.tv twitter.com uploaded.net webmd.com weebly.com wikia.com wix.com xhamster.com youporn.com zendesk.com zillow.com
Probably Different ImpactNote that not all of these sites were equally affected as some of them like Amazon are using multiple DNS providers. The Amazon main domains NS records do point to Dyn and UltraDNS. The same way probably none of the major adult sites was down as the also relied on at least two providers.
So while Amazon users probably got to the website after one DNS timeout and switching over to UltraDNS, Twitter and Github users were not so lucky and had to hope for Dyn to respond. It will be interesting to see if Twitter and Github will add a second DNS provider in the next time as a result of this.
The Need For "Multi-DNS"Reading different reports on this incident it seems to me the headlines are focussing on those sites using just Dyns DNS and not on those having a "Multi-DNS".
Detailed results on who is using which DNS domain can be found in the monthly DNS usage index.