Any old app can screen calls of well-known call centers...but what about the smaller, local ones? The Mr. Number app claims to identify 70 per cent of phone calls in the US, by asking its users to opt-in and share their contacts so they can learn from them.
This app doesn't only benefit people who wish to screen their calls in the face of telemarketers—it can also display people's details who aren't listed, though I'm not sure how they'd feel about that.
It's been around for a while on iPhone, Android and BlackBerry, but has just been updated with a status-sharing function that enables the user to switch on their status like they do with their favorite IM client. You could choose to say you're busy and don't want any calls right now, or that you'd prefer a text—or that you're ready and waiting to hear all the latest gossip. [All Things D]