I know a lot of folks using .dev for locally running "development" instances of websites/apps. Maybe .local is now a better choice.

.local was already the standard: http://en.wikipedia.org/wiki/.local

.local reserved for special mDNS functionality http://files.multicastdns.org/draft-cheshire-dnsext-multicas...

.local is reserved for mDNS. I'm not sure why you can't just use the host's real FQDN.

Because you might want to have multiple vhosts running on localhost, separated by hostname.

If you host is, say "zeus.barrera.io" you can use:

test-service-1.zeus.barrera.io dummy-server.zeus.barrera.i

Etc. No need to create new (possible conflicting, definitely not future proof) TLDs.

It's not about shared hosts (at least if I'm understanding the topic correctly) but about /etc/hosts entries on your local machine for your local machine. As in:

    my-test-thing-a.dev 127.0.0.1
    my-test-thing-b.dev 127.0.0.1
    my-test-thing-c.dev 127.0.0.1

Buying an actual registered domain for that sounds like it would be even more confusing than using an unregistered TLD because it makes it hard to tell which hostnames are expected to work across machines and which are strictly "works on my machine".

or .test http://en.wikipedia.org/wiki/.test

I used to use .foo, Google acquired that one last year:

http://icannwiki.com/.foo

Microsoft documents even dictate using .local, but if you have mDNS on your network you immediately start to run into problems.

I use .lan