I've been fairly happy with my eee pc but there are a few sites that are a challenge to use because of the small screen. Typically these are sites with high levels of interactivity.
Blogger - the only really annoying part is modifying the fonts/colours in the customisation area. With Firefox set to full screen I am left with a tiny preview to scroll in to see the changes.
Google Sites - I can't insert a text gadget. The input area extends below the 'fold' and there is no way to scroll down to hit the Save button - presuming that's what it is called - i haven't actually seen it. Other editing features in Google sites work just fine letting me use the scroll button on the mouse to get down to the bottom. Strange that the text widget is different.
Google Notebook - another one that's a bit challenging with the small screen, just not enough of the interactive area is available to work in, but the header stays firmly in view.
Other strange things I've found include Twitter fox pop up disappearing behind the subsequent tabs that I've opened.
Hmm - all Google services so far