Most apps in the market offer blacklist option where you can add those numbers you want to block. But this app takes an innovative way out to "whitelist" numbers. Want only calls from your boss for the next few hours? Whitelist him. No calls except the boss. Kudos to the developer for this unique idea!
Can't add numbers directly from address book?!? FAIL! UNINSTALLING.
Wonderfull app. A really different approach to the usual call blocking technique.