Siri can no longer find my home # Whenever I wanted to call my land line at home, I would instruct Siri to "call home" (my home number is listed as home in my contact list) She would respond by saying "calling home" and the call would be made. Now she says "I dont have a home number for John" (this is my name). A friend is having the same problem. What has happened?
I had similar problems, only Siri was not finding contact information of any kind, was not locating my friends, and not opening apps on command. I found that the problem was that Siri was having an issue with opening apps was causing all problems listed. To fix I used a Cydia app called iFile to locate the following files:

/var/mobile/Library/Caches/com.apple.LaunchServices-045.csstore
/var/mobile/Library/Caches/com.apple.mobile.installation.plist


Delete both the files, close iFile, and reboot device. After restarting all your apps will be gone and they will come back one at a time. Took only a few seconds for them all to load. Tested Siri and all my problems solved.

I'm using a jailbroken iPhone 5 with 6.1.2