On a related note to the hang-up calls I mentioned, Slashdot pointed to a N.Y. Times story on so-called “ghost calls.” The story is a good primer on what web resources exist for tracking these calls. In other words, this story describes the kind of battles I’ve been fighting for the past few months.
The story also provides an interesting tip for defeating the calls that I hadn’t heard of before:
Because the predictive dialers try to identify answering machines by measuring the amount of time that someone or something speaks, one way to defeat them is to give a long greeting, as an answering machine does, rather than a simple hello followed by a pause.
Be sure to check the comments in the Slashdot post, as the geeks (as usual) have excellent information on how these predictive dialers really work.