Why google domain one more dot still works?

I am not sure which forum shall I put the question.

Please check http://www.google.com./ still can be linked to google

As well as http://www.yahoo.com./ and http://www.msn.com./

but some sites are not working for adding one more dot at the end.

My question is what the extra dot at the end really mean?

ps: from above link google has PR0

 

It even works for my domains.

 

it seems that work for all domains not only for google

 

ITs actually valid in the http protocol i am told.

Depending on the way the HTTPD is setup - you may or may not notice any difference.

I know it cripples most websites running lighttpd. They tell me though they are just following the RFCs and therefor the likes of apache etc are wrong.

Oh well!

 

I just tried it on one of my Lightspeed servers and got the Apache Success page, so it's treating it as another domain. No doubt seeing it as a second level domain such as .com.uk or similar. My CentOS server displays the domain as normal though.

 

it also works for my websites...

 

Interesting - works for all of my sites.