At first I was furious. I had a question to a tax advisor. He responded promptly sending me a compilation of information in a file with the extension <.docx>. Arrrggghhhhh.
I am sorry but I am not on Windows Vista and I don't use office 2007. And I am not planning to do so. Nor am I planning to ever install a "fix pack" (or whatever they call it) so that I can open such files with my old MS Word application. Because, clearly, Microsoft with their <.docx> and other Office 2007 formats not only are a pain in the neck for users by not allowing for full interoperability but also create yet another lock-in situation.
So once I had calmed down I simply sent the stuff back to the tax advisor telling him that I can't open, can't read that file and asking him to save it as <.doc> or - even better - <.odt.>. After all, it should be clear to the world: it is not me who is locked-in; it is those who decide using Vista and MS Office 2007. Everyone in the same situation needs to make clear that it's them who have the pain, not us who strive for interoperability and use open standards based formats.