1. Asus eeePC: Yes, I've got one. And my kids are addicted to it. The eeePC has proven that there's a market for low-cost sub-notebooks (quietly driven by Linux). Will Canonical successfully leverage learnings from the Asus eeePC, or will Canonical wind up competing in some ways with the device? It sounds like the netbook is designed more for handheld device use, while the eeePC truly is a mini-notebook.
2. Google Android: Yes, Android is primarily for next-generation smart phones. But it's got a ton of hype and numerous backers across the hardware, software and service provider landscape. As developers get tied up with iPhone 2.0, Google Android and other big consumer projects, will they have time for Ubuntu on netbooks?
This shouldn't be too much of a problem, since Ubuntu has massive user and developer communities. The bigger problem may be the press, which will be focused heavily on Android toward the end of this year -- right around the time that netbooks are expected to debut.
3. Apple iPod Touch: Canonical says Ubuntu netbooks will allow consumers to "enjoy email, instant messaging, Internet surfing and on-line access to photos, videos or music with an affordable, reliable device." That sounds quite a lot like the Apple iPod Touch ("iTouch"), yet another Apple device that my nephews are addicted to. Canonical will need to draw clear lines of differentiation between netbooks and the iTouch.
4. OEMs: Dell seems pretty pleased selling some PCs with Ubuntu Linux preinstalled. But can Canonical convince big PC companies and device makers to back Ubuntu netbooks? We should have some answers later thus year, when OEMs begin to introduce netbook devices, according to Canonical.