Three cases in point:
DaddyTypes: Two years ago, I was a lucky "winner" of a DT t-shirt in the Bizarre Book contest. Here's my entry and here's the post that says I won. As instructed, I sent my size request and mailing address to the blog owner. Nothing ever arrived.
NinjaPoodles: Another one that's almost two years old. Here's the post that announces the contest and here's the post that says I won a book. That's Oliver and Penguin right at the top. I sent my mailing address. No book.
Mod*Mom: This one is more recent, April of this year. Here's the post that announces the contest and here's the link to the comment she left on my blog saying I won a set of Method toilet cleaning products. After my earlier experiences I decided to pursue this one a bit more carefully. I have sent Mod*Mom three e-mails with my mailing address. I included all the links in my last message to her. No response.
The products themselves are irrelevant. I get along just fine without them. Though CD would look nice in a DT t-shirt, he's got an entire drawer of shirts he's never worn. I was just hoping for a change of pace from the standard fare of computer geek shirts. No, it's the principle here. If something happened and you are no longer able to deliver the goods, just send an email, or put something on your blog about it. Stuff happens. Big deal. We move on. But tell me.
In the interests of full disclosure, I recently held a small contest to guess the date I would get my first piece of spam in my new work e-mail account. Only one person seems to still be in the running to win the $25 iTunes gift card, and that's Allison of AllisonSays. All the other dates have passed with no spam so Allison's guess of July 29 is the winner. Just to keep it fair, I'm going to wait until the 29th to send her card.