Take URL's, for example.
Back when George Lucas was working on the first of the three prequels (and we were still under the impression that they might be worth a damn), some savvy online folks discovered that his company had registered a buttload of URL's that had new character names in them. It was their pre-emptive strike against cybersquatters, but it inadvertently revealed some details of the new film that people were clamoring for.
This practice still exists today. Not just for movies but for any sort of large enterprise. Like, say, presidential campaigns:
The GOP sure knows its base, you gotta hand it to them. A little digging by Govgap.com reveals that www.votefortheMILF.com links directly back to JohnMcCain.com, then on to Sarah Palin’s page and a video message.