I wouldn't trust the listings on this site - http://www.100toplibrarysites.com/?cat=Free%20Email
For one they list freeze.com (a known malicious site)- http://www.mywot.com/en/scorecard/freeze.com
(blocked by many host file blocking lists, antivirus and WOT)
Many of the links are out-dated, some are parked domains.
Watch about clicking any links on that website, Avast blocked some of them, others were blocked by MVPS Hosts.
Looks like the site hasn't been updated in many years.
Netscape Mail for example hasn't been in service since 2006, it is now part of AOL Mail.
Probably why Gmail isn't listed.
Thanks.