Appendix B: Domain Names
There is no standard practice for creating a mobile version of a Web site. Some operators have one address for all traffic, others use a subdomain (mobile.company.com), some have bought into the "mobi" top-level domain, others have set up separate domains entirely.
The author asserts that separate domain names "Will almost never be a good solution" because it requires the operator to communicate different domain names for different channels an users tend to focus on a single address for a firm.
The mobile subdomain is a compromise. An url like mobile.mycompany.com has the "authority" of the second-level domain, and is recognized as a mobile site, but also needs to be promoted separately.
The mobile top-leve domain (.mobi) has similar strengths and weaknesses to the above. (EN: And it's worth mentioning that it never caught on - like "tv" and 'kids' and 'xxx'. Users are stuck on dot-com and there never has been much success in getting adoption of a new top-level domain.)
Ultimately, any separate domain name for a mobile site leaves companies with a problem of having to promote two different domains ("Visit our website at www.us.com and our mobile site at moile.us.com" or www.us.mobi or whatever")
One solution would be to provide a single URL in all marketing, but rig the DNS server to detect user-agent and send mobile users to a mobile site. The drawback is that this is not a widespread practice - in general, going to a "www" address takes the user to a Web site that is not mobile-friendly, so users may be unwilling to "try" your site unless they have experience with it.
(EN: Another issue here is misidentification. There are instances in which the site doesn't recognize a mobile device and shunts users to the web site, or worse, when it misidentifies a user as being mobile when they are on a computer and misdirects them to a mobile site. The latter is a particular problem when bandwidth detection was used.)
Even in that case, promotion is necessary to assure the audience that their "www.us.com" address works for both Web and mobile - but it's suggested this is an easier approach.
(EN: This problem remains, even today, though there are more novel solutions in mind to make a single site work for both channels - that is, not redirecting DNS to a mobile site, but having the main Web site adapt to suit the mobile channel. It's also getting easier to do so, as bandwidth and display capabilities are increasing - but the drawback is that this fails to consider the unique needs of the mobile user and treats the device as a tiny computer.)