It's all about the apps. With a smartphone, the mobile OS and default apps just form a foundation, but it is the apps that you apply on top that foundation that make the device uniquely yours, and enable it to be the indispensible tool you need it to be. For today's 30 Days With Windows Phone 7 post, I am going to take a look at the apps and the Windows Phone 7 Marketplace that sells them.

The Apps Arms Race

It is firmly established that Apple's iOS has the most apps. Apple has set the bar for app stores, and it has hundreds of thousands of apps to choose from. Microsoft's Windows Phone 7 Marketplace has only 30,000 or so. While it says something about the platform as a whole that so many developers would choose to create so many apps, it is not the only measure.

A recent article on PCWorld points out that the sheer volume of apps in the app store doesn't really matter. It cites a Nielsen survey that indicates that the vast majority of time is spent on the same top apps regardless of platform. Users may have 100 or more apps on their smartphone, yet use fewer than 10 on a regular basis.

So, while it is impressive that Apple has more than half a million apps, or that Android has more than 250,000 apps, and it may seem like Windows Phone 7 can't compete with its measly 30,000 apps, the reality is that 30,000 is way more than I will need. As long as Windows Phone 7 has the 10 or 20 apps I actually use, it will be fine.

Windows Phone 7 Marketplace

Microsoft seems to follow Apple's lead in many ways. Apple's iOS syncs music, apps, and other content with its iTunes application--Microsoft's Windows Phone 7 OS does the same using Microsoft's similar Zune software. Apple's App Store is accessed through iTunes. The Windows Phone 7 Marketplace is accessed through Zune.

When I click on Apps it opens to a default view that shows me some featured and recommended apps, and displays a list of the top 10 paid, and top 10 free apps. On the left side of the display is a listing of "Genres"--the various categories of apps, such as entertainment, sports, personal finance, news + weather, etc.

I clicked on the "Social" genre to get the Windows Phone 7 versions of apps like Facebook and Twitter so I can stay connected from my Windows Phone 7 smartphone. Google+ doesn't have a Windows Phone 7 app yet, so I will have to resort to using the mobile website for that social network I suppose.

The Windows Phone 7 Marketplace shows me a thumbnail icon for all of the various apps available along with the price of the app. One thing I really like about the Windows Phone 7 Marketplace , though, is that it also shows me the app's star rating. I like that I can see at a glance whether other users think the app is any good, or if it's total crap rather than having to click on each app one at a time.

One thing that I am not a fan of is that the listing of the Genres on the left of the display scrolls away as I go down the list looking at the apps. I think that the list of genres should be static so I can switch genres easily without having to scroll all the way back up. For that matter, there should also be a way for me to jump back to the top without having to scroll all the way back up.

From the Phone

On my HTC HD7S, the Marketplace app is one of the default apps on the start screen. I have moved it down lower on the start screen view, but I haven't removed it.

When I tap it, the initial load of the Marketplace seems to take a while. But, eventually the app is live. From here, I can choose between the AT&T AppCenter, the HTC Apps store, or apps, games, or music from Microsoft.

I tapped on the Microsoft apps and the app gives me access to the same list of genres as the Marketplace site within Zune, but this one also includes links for the AT&T AppCenter and the HTC Apps. I can swipe left and right on the display to go to Top, New, or Featured apps.

As I drill down, the apps for the specific category are displayed along with the price and star rating just as they are in Zune. With a few taps, I can buy and download the app to my phone. The default payment method is to simply tack the amount for the app onto my AT&T wireless bill, but there is also a link that lets me charge it directly to my credit card on file with AT&T, or add a new credit card if I choose.

I have to admit that I have already found a few apps that I like and use on my iPhone that simply don't exist on Windows Phone 7. Things like Google+, my bank's mobile banking app, Madden Football, etc. So, I can't honestly say that Windows Phone 7 is in the same league as the iPhone at all when it comes to apps.

Yes, 30,000 is a fair number, and I am sure I can find equivalents for most of the important apps I really use, but until or unless Windows Phone 7 gains some market share, it will continue to be an afterthought for companies and developers and it will get apps later or last if it gets them at all.

But, for the new kid on the block it seems to be progressing nicely, and it offers an app shopping and buying experience that is at least equal to its rivals, and in some ways it's a little better.

Read the last "30 Days" series: 30 Days With Google+

Day 3: introducing Live Tiles