I'm afraid that instead of that Nokia will just launch their own (and quite probably isolated/crappy) version of these as part of the grand Ovi strategy. Why is it so difficult for companies to understand that we want to use the web services that we already use and where our friends are?

Of course, Nokia could surprise us positively, and generate a cool, mobile-friendly UI that would still let us stay in touch with the community sites we've been using all along. Flickr integration etc...

At this point following Apple's guidelines is most likely a safe bet. That way your mobile site will work nicely with both iPhone and the S60 browser.