m. vs .mobi

GigaOM今天討論一個蠻有趣的主題，Mobile WEB的Domain Name的問題，由於最近越來越多的WEB開始提供Mobile版本，但是他們都不約而同的使用m. (m.twitter.com、m.yahoo.com、m.google.com、m.ask.com、m.youtube.com)，而沒有使用.mobi的domain，而文章中以twitter的回答來當例子

We use the m because it's the shortest possible meaningful sub domain and typing on some phones is a pain. We didn't launch [the main site] with auto-detection because it would have held back the launch (it's difficult).

但是很快的dotMobi的CTO James Pearce在comment中回覆了，dotMobi的說法是

1) Users can't be expected to guess whether a given site's mobile interface is m.thingy.com, mobile.thingy.com, thingy.com/mobile or (even!) thingy.com/xhtml. Outside of .mobi, there's as little sign of convention as there is with the diversity of different devices

2) .mobi, as the top-level-domain designed for mobile, provides a lelev of trustworthiness to the user (although they may not explicitly know it). We have a set of best practices, developed with the W3C, that we expect our registrants to build their sites to. And theoretically the right to disable sites if they flaunt basic principles of mobile suitability.

3) It's not blindingly obvious to a non-technical user that m.site means mobile. Put it on a billboard ad and people are going to scratch their heads. I would have hoped that a URL ending .mobi has a fairly obvious intention - even to my grandmother.

I think autodetection does have an impact of course - being able to spot a mobile device and route accordingly. But .mobi is also about more than markup suitability - it's also about providing services suitable for the mobile context. And I believe users should a) be given mobile-relevant services by default, but b) still be allowed to go to the full PC site should their patience (and browser's abilities) permit it. With auto-detection, that's a very rare choice.

其實，兩方的說法都有點道理，不過我本人是比較傾向使用m.而不是.mobi啦(因為Big Player都是這樣用嘛)，不過雙方針對auto-detection的看法，倒是都一樣。