Is anyone else starting to see this happen?

I’m finding it more and more common as people update their PC’s and laptops, they get the new edition of Office (2007), and just don’t realise that the file formats have changed and their files can’t be seen by others user. That, and when you do point it out to people, it’s real easy to forget to save files to an older format. Is there a default file type setting in Office 2007? How are people dealing with this problem? I can only see it getting worst over the next few years, as 2007(+) becomes more widely used.