Netbooks triggered new lows in laptop prices of under US$300, Shiffler said. That pricing pressure is now trickling into mainstream laptops, which have seen prices hover around $500, dropping below $400 in some instances, he said.

Netbooks are looking more like mainstream laptops as they get more expensive with larger screen sizes and keyboards, Shiffler said. At the same time, the prices of mainstream laptops are falling, which blurs the line between both the laptop categories.

But anecdotal evidence also suggests that people are finding out that netbooks have limited capabilities and are not substitutes for full-screen laptops, Shiffler said. That could drive some people back to buying mainstream laptops, he said.

Also challenging netbooks are ultrathin laptops, which are low-end, thin and light laptops priced starting at $500. However, ultrathin laptops have just hit the market, so their impact on netbooks cannot be assessed.

"There's a market for a low-end notebooks, it's just not clear if it's only the mini-notebook. It's going to get very interesting to see what happens," Shiffler said. The shipment of netbooks -- which Gartner refers to as mini-notebooks -- will reach 21 million this year and 30 million next year, he said.