I recently bought an ASUS EeePC 1000HE, and have been very pleased with it. I immediately installed Ubuntu 9.04, and was delighted to find all functionality working out-of-the-box.
However, the one thing that has puzzled me the last couple of weeks has been random websites loading in Firefox as I was scrolling web pages (with the two-finger multi-touch functionality), or sometimes even an error dialogue saying the URL was invalid and could not be loaded.
It turns out that this is because the touchpad sometimes interpreted my scrolling as a middle-mouse-button click - which (previously unknown to me) causes Firefox to load the text in the clipboard as a URL.
This behavior is easily disabled by going to about:config in the address bar, searching for middlemouse.contentLoadURL, and changing the value to false.
Hopefully this might help anyone experiencing the same issues as me. There is more info on the middlemouse.contentLoadURL property at MozillaZine.