[dsl]

Some small subset of pool servers run an HTTP server that redirects you to www. Not all of them. You just got lucky.

[Volundr]

That's exactly right. www.pool.ntp.org is the project site. pool.ntp.org is for getting an NTP server. Which one you get will depend on your location and random chance. That server will run NTP, but what it happens to run on port 80, if anything, is up to the operator of the server.

[euyyn]

I must be lucky too, as I got the same result from both.