This week could bring answers we've thus far lacked when it comes to the iPad's potential for mass-market popularity. Apple (NASDAQ:AAPL) will begin taking pre-orders for the device as soon as Thursday, the website reports, citing an unidentified yet "reliable" source familiar with the Mac maker's plans.

I'd love for this report to be true. Data is the lifeblood of good investing decisions, and right now we have far too little information when it comes to the iPad.

Buying blind
All we really have are specs and dates. For example, we know from Apple's press release that the iPad will sell for as little $499 for the Wi-Fi edition, and that 3G models built for AT&T's (NYSE:T) network will ship in April.

We also know from surveys that there's reason to be skeptical of Apple's ability to generate demand for the iPad. Electronics reviewer Retrevo polled more than 1,000 site visitors and found that, even after seeing it, 52% were still uninterested in the iPad. Another 18% hadn't seen it and also weren't interested in buying.

But that's just one survey. Another says that one in five physicians were interested in the iPad; not much of a surprise given President Obama's push to create an infrastructure for electronic health records (EHR).

What we're missing is any hard evidence of demand for the product. A pre-order website would change that.

A solution searching for a problem
Part of the problem with the iPad is that there's no clear purpose for it. Unlike's (NASDAQ:AMZN) Kindle or Barnes & Noble's (NYSE:BKS) Nook, the iPad could be a movie player or an e-reader or a jukebox or a photo album. From the press release:

Import photos from a Mac, PC or digital camera, see them organized as albums, and enjoy and share them using iPad's elegant slideshows. Watch movies, TV shows and YouTube, all in HD or flip through pages of an e-book you downloaded from Apple's new iBookstore while listening to your music collection.

It's a floor wax! No, it's a dessert topping!

iFans smile at this flexibility; it's technically impressive. And yet, aside from smartphones, the jury's still out on combination electronics. For every clock radio, there's a universal remote. The iPad could be either at this point -- it's a solution searching for a problem.

Apple CEO Steve Jobs knows it, too. As Darrell Etherington of The Apple Blog pointed out shortly after the iPad's official unveiling, Jobs spent ample time at the end of his presentation justifying the product, wondering aloud if Apple would be able to "establish a third category of products." Not exactly the vote of confidence I'm after as an investor.

More broadly, I'm frustrated that Jobs and Apple haven't done the necessary work to position the iPad as an alternative to something other than hip. As in, iPad owners = hip. Non-owners? Not so much.

Jobs, for his part, described the iPad as "magical and revolutionary." If only we knew what it hoped to revolutionize.

Publishing is where the iPad could have the greatest impact. The aforementioned iBookstore is a direct shot at the Kindle. Within, Apple had hoped to sell e-books for as much as $15 apiece, well above the $9.99 watermark Amazon long ago made standard.

I say "hoped" because, according to a recent report in The New York Times, Apple is planning to offer some best-sellers for as little as $9.99 apiece, matching Amazon's Kindle pricing. So much for the iPad as savior of the publishing industry, eh?

Bring back the PDA
Maybe that's unfair. What I find fascinating is that, in many ways, the iPad is an unfinished product that's going to benefit from, or be killed by, the ingenuity of partners and developers who see it as a platform for making money.

You might say that Apple is acting like Google (NASDAQ:GOOG). Build a product, give it features, and then let the wider world experiment with it, adopt it, and improve it.

It's an unusual strategy for Jobs, and it's put him in the interesting position of going on the road to convince potential partners to sign on. Jobs recently visited New York to meet with executives of New York Times Co. (NYSE:NYT) and News Corp.'s (NASDAQ:NWS) The Wall Street Journal. Clear positioning could help with these sorts of discussions, more of which Jobs is sure to have.

My advice? Use the iPad to resuscitate an old category in a new form: the personal digital assistant. Only in the case of the iPad, it wouldn't be so much a schedule-keeper, as Palm's Pilot was, but really an assistant -- a smart, digital errand boy capable of making recommendations, eliminating repetitive tasks, and fetching any sort of content I want, when and where I want it, for a reasonable price.

That's the sort of product I'd pre-order.

Is Apple's iPad positioning opaque? Make your voice heard using the comments box below.