I had high hopes for netbooks bringing about an increased mindshare for Linux for ordinary users. This didn't quite pan out unfortunately and it's nigh impossible to find a Linux netbook at a brick and mortar store these days. Users loved the low price and mobility of a netbook, but (seemingly) didn't appreciate the lack of a Microsoft operating system powering their everyday computing.
I think this really was a case of an opportunity missed with respect to Linux. Had we seen a more unified effort on the part of one of the major distros (Ubuntu would have been good) to market Linux as a major selling point, I think we may have seen a better result in converting some users. Even if it was only on their netbook, it was still a golden opportunity to display the potential of Linux to an audience that likely had little experience with anything other than the Redmond OS.
Is Chrome OS going to be the big win that Linux needs to gain a wider acceptance for everyday (home) computing? It might be. I think it really depends on how the OS is marketed to users. Google is a huge company with deep pockets and a great brand name and definitely has the clout to give Linux a much-needed push for the non-tech crowd. I suppose a lot of how this pans out for Linux in the wider sense really depends on how Google focuses their marketing efforts.
My prediction? I think that Google will market this as the perfect device for connecting to their web apps and nothing more. While the Linux kernel is going to be the workhorse for all of this, I think it's going to be lost in the marketing. The mindshare for Linux amongst ordinary users will be the same 18 months from now as it is today and they still won't know what Linux really is or how is could help them. If Google isn't able or willing to do it, I'm not sure that it's going to get done in the short term. I just don't see Google OS functioning as a catalyst for Linux adoption as unfortunate as that may be.