iTunes on my iMac is not synching with my other Apple products.
Can anyone answer why my iTunes on my iMac is not synching with my other Apple products. If I buy a song via my iPhone, it shows up on my MacBook Pro, iPhone, and iPad 2 in the "Purchased" library but not on my iMac. Also, for what ever reason when I open iTunes it says Previous iTunes Library at the top and my MacBook Pro simply says iTunes
iMac, Mac OS X (10.7.4)