To redirect to www.example.org I need a server listening at example.org. If I have www.example.org on heroku because I don't want to run a server, I suddenly need a server just for that redirect that I need to have because I don't want to run a server.

Or just use http://wwwizer.com/

EDIT: Or use DNSMadeEasy, they provide HTTP redirect options as part of their service (although I wish the default option would not be to wrap the target URL in an iframe...)

Or use an S3 bucket with a redirect.

But there's already a non-Heroku server running for that domain, i.e. the one serving DNS requests. That server can be re-purposed to do HTTP-level redirects, too, and indeed many name server operators offer that feature.

It does, but then can you do that without using an ALIAS record, which is one of the reason invoked to use "www"?

Also, web-centric is fine, browsing the net is 99% of my URL manipulation, and I'm a developer that has to work with web APIs.