Skype has become an essential business tool for many, especially those looking to tame travel-related telecom costs. The popular VoIP services work around the globe and support many desktop and mobile platforms with dedicated applications. On April 22, Microsoft made version 1.0 of Skype available to its Windows Phone smartphone platform, following a beta period of about two months.

I downloaded and installed Skype version 1.0.0.0 on my Nokia Lumia 800 and gave it a whirl. Skype for Windows Phone should be one of the crown jewels in Microsoft's mobile platform (after all, Microsoft owns Skype). Instead, it feels incomplete and lacks polish.

The user interface for Skype borrows heavily from Microsoft's Metro UI concept, with multiple pages in the app that are accessed by swiping sideways to the left or right. The UI uses Skype's well-known white-and-blue color scheme, and all the requisite Skype sounds are present.

Once you've logged in, the first screen visible is the contact page. Rather than highlight or show you which contacts are online, the app simply shows you the entire contact list that's stored on the device. I thought perhaps swiping sideways would parse that down to my Skype contacts, but that's not the case. Instead, that only shows you a list of recent calls. From the main screen, you can also choose to search through your contacts or open the dialpad. For an app that's supposed to help make phone calls, the button to open the actual phone is a bit too small.

In order to see your Skype contacts, you have to press a ridiculously small button that says "All". Only then can you choose to see the list of people who are available for free voice calls and IM. Your Skype contacts appear in the Windows Phone app just as they do on a desktop client or the Android/iOS apps.

You know what's also too small? The button used to access and manage your profile. It's a teeny little thing tucked into the top-left corner of the app. The settings tools are anemic at best, and only let you toggle on/off automatic sign-in.

Skype for Windows Phone lets you voice/video call and IM other Skype users for free over both 3G and Wi-Fi. In my tests, it worked perfectly over both network types. Call quality was outstanding, I was very impressed. Calls were connected quickly, and I had no trouble reaching other Skype lines and landlines. The same goes for IM. IM conversations were fast and furious. Video calls showed mixed quality, but they were good enough.

The app covers these basics just fine, but falls flat in other ways.

For instance, Google has done some great things with Google Voice--especially for the Android platform. The latest version of Google Voice for Android 4.0 Ice Cream Sandwich integrates flawlessly with the native dialer and voicemail system or the operating system, for example, merging the two services into one.

This is what Microsoft needs to do with Skype, but hasn't. Instead, the app is siloed from the operating system completely, and is a stand-alone application.

Worse, Skype for Windows Phone leaves out one critical feature--it won't run in the background. This means if you close the app, it not only shuts down, but also signs you out of the service, leaving you unreachable to other Skype users looking to connect. I tried using Windows Phone's fast-app-switching powers to get around the problem, with no luck. Every time I returned to Skype, I had to sign into the service anew.

Last, Skype won't run on Windows Phone "Tango" devices. Tango is the low-end version of Windows Phone that functions on half the RAM that other versions of Windows Phone use. Apparently Skype can't function with such little system memory available. This means those who can only afford low-end smartphones won't be able to realize the cost savings possible with Skype.

Based on these factors, I'd call this basic Skype application a place-holder at best while Microsoft--hopefully--works on much deeper integration between Skype and Windows Phone.

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