Once again Randall is on the money here.
Attn: developers of mobile websites. If I follow a link from Google (or, say, an obfuscated short url from someone’s Twitter post) to a specific page on your website, by all means sniff my user agent string and give me a mobile-friendly layout because I’m on an iPhone, if that’s your thing, but don’t dump me on the homepage of your mobile website.
Here’s an example: had to look something up on the website of aussie supermarket chain woolies, but it’s basically impossible to browse any content on their main website on an iPhone. Direct links in from Google dump you at i.woolworths.com.au. So you hit that “visit the normal website” link down the bottom and get the homepage of their main site. Oh and there’s the link to that thing you were looking for…. So you tap the link and… oh you’re on an iPhone? Yep back to i.woolworths.com.au for you. Brilliant.