There's been a lot of noise recently about mobile-specific domain names - a .mob extension, for instance - which would allow service providers to mark a given resource or site as being mobile specific.

I think this is a terrible idea.

But to stop myself relentlessly shouting about it elsewhere, here's the sum total of my thinking on why it's bad:

1. We can already differentiate services by using a prefix to the domain name: compare and; you don't need a new domain name to do this.

2. Saying a service is "mobile" doesn't tell you anything about which "version" of mobile it is: WAP? XHTML? cHTML? If you plan to automatically determine which version you're going to deliver, that's great: but in this case you don't need a separate domain name. Just hand out "" and redirect as necessary.

3. There's an underlying assumption that URLs are relevant to everyday users of mobile services - that in a few years time, we'll all be tapping addresses into our handsets to access sites. Personally, I don't like this: the reach of mobile goes way beyond the reach of the fixed-line internet. People who don't know or care about underlying technology use mobiles every day of their life, and it seems rather arrogant of us (mobile service providers) to expect them to learn about browsers, servers, sites, and URLs in order to get them to spend time and money with us. The mobile internet needs to be easier than the web, rather than apeing (sp?) it on a small screen. Just because the people building the mobile Internet understand URLs doesn't mean that users have to.

So why are we seeing proposals like this?

1. Domain names are a good way of making money out of thin air. Convince people they need to own every possible representation of their name, and keep coming up with new representations (.biz, .ltd, and so on) to sell them.

2. Mobile is where it's at right now in certain industry circles, and being fashionable attracts all sorts of loons (as we saw in dot-com times).

3. This reason's a little less solid: convincing people to access services through URLs (as opposed to portal menus) helps to get individuals thinking beyond the limited portal their operator presents them with, and maybe weakens the operators control over their customers experiences. I'm not completely convinced by this one though - especially as Vodafone (or at least, one bit of Vodafone) seem to be backing the proposal for .mob domains.

By the way, if you're a developer and find typing long URLs into a handset to be a pain, I recommend checking out TinyURL, which works just dandy for mobile.