ASUS' netbook sales could drop by 25 percent or more next year due to the effect of the iPad and other tablets, reported industry estimates claimed today. The system builder is estimated to be shipping six million Eee PCs by the end of this year, or 50 percent of all its systems, but would ship just four to 4.5 million in 2011 with tablets factored in and would make up just 25 percent of its computers. The 2010 estimate was itself a drop from 6.8 million in 2009, Digitimes' contacts said.