Apple's new iPad has helped to define the broader tablet market, even though it has yet to ship, according to research firm ABI Research. The firm said Tuesday that shipments of tablet devices - defined as touchscreen interface devices measuring five to eleven inches with WiFi, video and gaming capabilities, will measure four million units in 2010, and rise to 57 million units by 2015, prodded along by the iPad.

"Apple's iPad is not the first media tablet," senior ABI Research analyst Jeff Orr said in a statement. "But it does help define this new device category."

According to the firm, the main focus of tablet devices will be for entertainment, and he said they will not replace laptops, netbooks, or mobile phones. In addition, ABI said that it believes tablets will remain a, "premium or luxury product for wealthy industrialized markets for at least several years."

The firm also believes that the iPad will help offer other tablet makers, especially smaller companies trying to bring new devices to market, exposure that could boost their sales.

"New entrants to this market are at a disadvantage since they lack the retail relationships and network operator agreements already built by the more mature vendors," Mr. Orr said. "Surprisingly, Apple may have done them a favor by raising the public profile of the whole media tablet category."

Jeff Gamet and this reporter discussed similar ideas in the most recent episode of The Apple Context Machine podcast, published over the weekend. Our comparison was to the boost that Apple gave USB with the introduction of the USB-only iMac.

USB had been around for some time before the iMac, but did not explode in after the iMac's release, when electronics vendors rushed a barrage of USB devices onto the market. ABI's research suggests that iPad could have a similar effect on the tablet market, boosting awareness of and exposure to competing devices.