It's a sad state of affairs. I often peek at the metadata of other people's online photos (with my Online Image-Data Viewer), and it seems that a lot of people with pro and semi-pro cameras set them to save in different color spaces, such as AdobeRGB, and present them on the web that way (and without even an embedded profile). The problem is not that they use a different color space to begin with, but that they use something other than sRGB for the versions they present online; they're ensuring that pretty much everyone will see the wrong colors.