Apple at the beginning, from 1977 to 1986 they were selling personal computer product. Then later on until 1997, Apple didnt have any specific product strategy. Things change after 1998 because Apple re-engineer them-self and start focusing on specific market.
Their first product at that year is iMac. The iMac featured modern technology and a unique design, and sold almost 800,000 units in its first five months. At 2001 they began selling iPod, at 2007 iPhone and finally iPad at 2010.
Apple product strategy nowadays is to create a strong integration between each product through simplicity.