When you consider the importance of fit, nobody should ever buy a gun that they haven't held in their hands. In fact, none of us should ever buy a gun we haven't test fired. (Nice if it could always be that way!)
In the real world, we have to take risks, especially if you're after a bit of a deal or you want a particular gun that isn't available locally. Smart risk takers, while they are willing to take risks, are only willing to do so after doing their due diligence. In the case of guns over the internet, that means finding out what you can about the seller and at least asking for good pics.
For me, buying a gun over the internet is an unacceptable risk unless the price is cheap enough that I expect I could get my money out of it even if it was a couple of notches lower in condition than that represented by the seller.
Strange coincidence that you should bring up this subject now, Fassteel. I bought my first gun ever this way last week. I think I may be the rotter that scouped the one Mad Dog was considering. Sorry, if I did Mad Dog, but I couldn't resist. I still don't have it to see what I got (great deal or screwed). I could post a follow up, if you're curious. If I got screwed, I deserve it - there were others asking for pics, so I just bought it, no pics, nothing.
I do have a code of ethics, though: I won't try to scoop someone else's deal if they bring it to my attention in the first place (not even ask the seller about it, in case he thinks he's got a bidding war going and gets harder on the original buyer). So there you go, if you ever want to make sure I don't scoop your deal, just PM me and ask me what I think of it. That way you know you'll have time to wait for the pics.