Is Apple iRadio late or canny?

(MoneyWatch) The Apple (AAPL) streaming music rumor mill is once again humming busily. The company has reportedly partnered with Warner Music Group, following a deal with Universal Music last month. Apple could announce its music streaming service as early as next week at the company's Worldwide Developers Conference.

You might wonder what it taking so long. Multiple other services, including Pandora (P), Spotify, and Rdio have a long lead time. But Apple has frequently entered a market late and come in with something compelling enough to knock competitors on their backsides. So, is Apple late with what we might as well call iRadio at the moment? Or will its technology and business model combine to cause grief to everyone else in the business, including Google (GOOG) and Amazon (AMZN)?

If the market action in Pandora shares is any indication, investors take Apple's threat pretty seriously. In midday trading, Pandora's shares were down nearly 12.5 percent.

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Apple supposedly has been working on negotiating rights to a streaming service for at least a year. Although Apple was rumored to get a lower cost for music than competitors, that apparently is not the case.

Many people have wondered why Apple, which was the biggest online music pioneer, has been so slow to enter the streaming music business. Actually, Apple has been in one part of the music streaming business -- since introducing its iCloud service, customers have been able to gain access to the music they've bought, either streaming it or downloading it to a device.

Where Apple has been notably missing is the streaming radio business, in which people can listen to music through a subscription service. Everyone else and their siblings already seem to have entered this business with a wide variety of business models, such as pre-existing standard channels, the streaming of particular songs, or user-defined types of music.

Apple tends to wait to enter a market until it has a clearly distinctive entry. The iPod was not the first portable music player, but it was the first to get a digital music store. The iPhone wasn't the first smartphone, but it made smart use of a touch interface.

The question becomes what Apple may have that others lack. Perhaps it is integration with iTunes, but that would not necessarily be a significant advance. Maybe Apple will depend on convenience to further tie users to its infrastructure apron strings.

Technology is unlikely to offer the major advantage. The business and user models would seem to be the greater competitive tools. Two things no other service does is completely bridge the gap between streamed and purchased music and allow storage of streamed music.

Both of these could be major advantages. Temporary storage of streamed music could allow a device to snag a block of music in advance of losing Internet access and then erase it when a connection returned. Integrating streaming with an iTunes music store would let consumers immediately purchase music that they heard and listen to suggested streams of music based on what they already owned.