Frankly I have not heard about Alexa for a very long time, wonder if it is valid anymore for SEO purposes?
Yes you can still use Alexa to check rank and performance of website. Because Alexa not only gives rank for the website but it also helps us to find out bounce rate, daily page views per visitors and daily time on site. So through these factors we can analyze performance of our website plus competitor’s website.
It never was valid; it always was a useless meaningless metric that counts for nothing Do you even know what the ALexa ranking is?
Go through this link you will get all about Alexa Ranking. http://www.avangate.com/avangate-resources/article/alexa-ranking.htm
I agree that, Alexa is nothing to SEO , and provides inaccurate results. It's just a semi-free tool that gives estimations of traffic and statistics. So to answer OP's question, Alexa is not and never was valid for SEO.
I always thought Alexa was just for fun there, I liked the look of it but it doesn't help you in anyway.
Alexa does have some premium tools for SEO, but you'd probably get better information from Google Search Console / Webmaster Tools and others.
Alexa is great for the vanity metrics: traffic volume/backlink stats from different sources. Many advertisers look at Alexa ranking to gauge the social proof or popularity of a website. The problem is accuracy-the numbers can be manipulated (you can look up Alexa inflation methods) and it cannot improve your organic search results. For SEO it is more effective to create great content that attracts high quality traffic and authoritative links.
I don't think so. Yes, Alexa is a tool that gives an idea how much traffic a site gets, but that's it. I don't think the relevancy is that much that it should be associated with SEO.
To answer the question; Yes. Alexa is valid. A lot of people use Alexa as a metric when selling or buying links or ads. The fact that it is partially irrelevant to SEO is a totally different matter altogether. My blogs ranking on various catalogs are indirectly connected to Alexa, Google PR and MozRank.
Alexa has now a days substituted by Google Analytics...Which offers the same features..But more accurate then Alexa.