Certain apps seem to start trends. On the BlackBerry right now the current big developer trend is call-blocking applications. I’ve gone through the MobiHand application store and have found tons of them, and even more under the new apps section. I can’t say I blame developers; it’s a great idea. Our cell phones are personal devices, smartphones even more so. We want to keep out unwanted callers, so why not install a call blocker app? While there are a number of such apps for Android, I’m a particular fan of Mr. Number. I tried the app on BlackBerry and enjoyed it, and once I found it available for Android I gave it a shot. It turned out to be a worthy download. There are two basic functions to the app, and call blocking is only one of them. The blocking allows you to create custom black and whitelists that will let you control who can call you. Once you have the lists in place you can decide whether you want to route the call to voicemail, or otherwise just pick up and hang up. The app will do either automatically.