We all know the story of Apple’s App Store: a gazillion downloads, more money than anyone has ever collected, and hundreds of apps from the mundane to the essential. But what makes for a great app store experience, and can anyone else come close?

Remember the dawn of the PC era, when all apps came in a slipcase and on five-inch diskettes? When you needed to get corporate approval to buy them and an IT guy to install them? How far we have gone, when a federal government employee for example can go to Apps.gov and with a few mouse clicks have their app of choice on their desktop.

There are lots of app stores and they seem to be cropping up everywhere. There is oneforty.com that keeps track of Twitter apps (what a great domain name). Sendmail’s Sentrion email server has its own place for you to download extensions, Intel has its appup.com where you can download apps for its Atom-based Netbooks, and each major mobile phone platform has its own app store:

• http://www.android.com/market
• http://marketplace.windowsphone.com
• http://www.palm.com/us/products/software/mobile-applications.html
• http://appworld.blackberry.com

I started thinking about this topic with this post from Dion Almaer, who now works at Palm running their developer relations.

Plug-in apps got their start in the browser world, which seems appropriate since the app stores all assume you start out with a browser or phone-based equivalent of some sort. But let’s look at the various components, and see what Apple does and doesn’t do well.

• Packaging. It isn’t just enough to create the app, you have to put together the right packaging, Web collateral, instructions (if they are needed) and screenshots to give potential customers a taste of what it does. Apple has to “approve” the app before it is listed in their store, and while the other stores don’t seem to be as heavy-handed, there is still a process to go through.

Android apps are very finicky. The same OS version on different phones will perform differently, a nightmare for developers. And iPhone and iPad apps are also different beasts and will take some coding to make sure the app works best on both platforms.

• Discovery. How do you find the particular app that you are interested in? Is it through a social network recommendation, organic search in Google, or using the store’s own search function? Several of the stores, such as the Android Marketplace, make for miserable searches, either classifying their apps into such broad categories that you spend too much time scrolling down the results. Or else they force you to use the in-phone versions to do the searching. Apple forces you to use iTunes, but at least you can look for your apps on your desktop and not suffer the tiny phone screen.

I did a quick search on all five mobile phone app stores for that four-letter word that describes one of those rude bodily noises. (I hesitate to include it in this essay for fear that I will run afoul of email content scanning services, not out of any prudishness.) On Apple’s store, there were more than 600 apps that matched – I stopped counting but clearly it could number in the thousands. Android’s Marketplace doesn’t let you search from the Web, when you go to an actual Android phone I got 111 matches. I got less than 15 matches for Windows, Palm’s and Blackberry’s stores each. Now, granted this is a less than representative sampling, but it just shows you at least how hard it is to find a particular app. And the more apps that are created for the store, the harder it is to find them, particularly if you are trying to use your phone to track them down.

Part of the problem with Apple’s AppStore is that you can only search the app title, with limited visibility in the remainder of the description of the app. That can pose problems for developers in how they name their apps.

• Payment. This is the hard part. Amazon long ago figured out how to do one-click payments and Apple makes it relatively easy, since everything happens within iTunes and your iTunes account. Some of the phone providers charge your apps to your phone bill, others to your credit card. Android’s marketplace uses Google checkout, Blackberry uses Paypal. With Windows Mobile, you can only buy apps from your phone. There are a lot of free apps too, and some developers make a limited free version, hoping you’ll upgrade to the paid version. According to one developer I spoke to, Android users seem more price-sensitive than others and aren’t as willing to pay, even a small amount, for their apps.
• Fulfillment and installation. Once you find and pay for your app, how do you get it to your desktop or phone? Just clicking on it doesn’t always do the trick. With Blackberry’s and Palm’s App stores, you send a link to your phone if you are browsing from your desktop. Another issue is how does the store deal with charge backs if you change your mind?
• Merchandizing. How do you promote your app, offer specials (such as free downloads under certain conditions, two-for-one coupons and the like) and include direct URL links to them?  Android and Windows Mobile both have direct URLs, although they can get long. Apple doesn’t make this easy, since they want you to use iTunes for everything.
• International users and other storefronts. In addition to the “official” ones for each phone platform there are dozens of other app stores for selling mobile applications, some specific to particular countries or carriers. Some are better than the vendor’s own, for example, the Palm-based PreCentral.net and androidzoom.com do a better job than the “official” Palm and Android ones shown above. These third-party stores have varying usability experience, and some even sell stolen goods, so there is that whole aspect too.
• Updates. Once you have your app listed, there is the process of doing regular updates and making sure these are posted across each storefront. This could be a nightmare if you are supporting multiple phone versions and have dozens of storefronts where your app is available.