The market share for Blogger decreased by 0.199 percentage points (from 1.229% to 1.03%) for all sites, more than any other segment during the same period of time.
We detected the following sites were using Blogger
goo.gl
blogspot.com
blogger.com
blogspot.ca
blogspot.de
blogspot.fr
How We Detect Installations of Blogger
Meta
A CMS will sometimes include a meta tag within the html of each page. This is usually a "generator" tag like <meta name="generator" content="What CMS" /> but could also be "application-name", "Powered-By" or anyting else the CMS creators decide to use.
Markup
If a CMS doesn't have meta tags, it will often have other uniquely identifiable html markup. This can range from unique html comments, ids or classes.
Domain
Some content management systems also offer hosting. A website hosted on a CMS developer's domain is a dead giveaway.