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Comment by smarx007 | Hacker News Reader

How does Alexa work? It seems to me it’s hard for anyone except Google Analytics or Cloudflare to build such a service.

They used to have its own toolbar that tracked which websites users visit.

After that, they've paid other browser add-ons to add their script and some websites voluntarily gave them their data by adding their tracker.

It says so right on the about page (warning: unusable on mobile): https://www.alexa.com/about

Yeah, it was also really handy for figuring out how to attack various web properties, as they frequently indexed administrative pages that were secured through nothing but obscurity, as the toolbar was most popular with amateur (and (im)professional) webmasters.

Ah, the good old days.

Interesting. I wonder if Apple privacy policies killed it. Or if the fact everyone is using the same 10 web sites for everything has eroded the need.

You'd assume that this would give a super biased sample of the population that would skew boomer+.

It was always biased, and it's only gotten worse over time as browser toolbars have ceased to be a thing and data collection in browser extensions has been heavily discouraged. I have to wonder if that's one of the reasons they're phasing the product out.

Initially, it was mostly by monitoring the traffic of users of the alexa toolbar, https://www.alexa.com/toolbar

I think they moved on to more broad data sources, possibly purchasing data from ISPs.

Read between the lines as to how this similar product from Cisco works.

http://s3-us-west-1.amazonaws.com/umbrella-static/index.html

Thanks! Goodness, only raised more questions:

1. What is Umbrella? See http://info.opendns.com/rs/033-OMP-861/images/OpenDNS-Global...

2. What is Passive DNS? See https://docs.umbrella.com/investigate-ui/docs/passive-dns

Handwavey "proprietary methodology" using data from "millions of Internet users using one of many different browser extensions" and "direct sources in the form of sites that have chosen to install the Alexa script."[0]

Translation: trust us

[0] https://www.alexa.com/about

Google Analytics would only work on sites that run Google Analytics, which would exclude sites run by the other big tech companies. Alexa worked because their toolbar addon would record every site their users went to, regardless of what was running on the site.

I remember vaguely that they got their metrics from a browser toolbar.

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