Once you enter a number or contact name, DeskSMS displays a field on the site for entering your text message, which is limited to 160 characters. You can also call the number you've entered, but the phone call will be placed from your actual Android phone, not your computer. This could be a handy way to make calls if you're already wearing a headset, but beyond that, it's not terribly useful.
More useful is DeskSMS's integration with Google. It sends a copy of text messages that you've received to your Gmail or Google Talk accounts, if you'd like. This allows you to see and respond to your messages from yet another interface, which is handy if you're already using those services.
Still, DeskSMS has its limitations. It doesn't allow you to send MMS messages, and I wish that it offered a conversation view. It doesn't display your texting history, which would allow you to view past conversations. And even when you get a text in response to one you've sent via DeskSMS, the Web app only displays it in a pop-up notification, it never adds it to the texting field you use for composing messages. When you consider that these limitations come in an application that costs you $5 a year, well, that makes DeskSMS even harder to recommend.
Mysms is the only service I tested that works on iPhones and Windows Phones in addition to Android devices. It does require that you install an app on your handset to use it, but its desktop component is not-solely browser-based. It's available in a desktop client that you can download and run locally on your PC...and it's the only product here that does. That's why mysms looks good on paper. But this free service leaves something to be desired when you actually use it.
To use mysms, you first install the app on your phone. Once set up, it sends you a text message with a PIN. You enter that PIN in whatever version of the application you'd like to use on your computer: The desktop version (available for Windows and Mac) or the Web app, which runs inside a browser. Mysms also is available for tablets running Android or iOS.
The Windows application and the Web app feature nearly identical interfaces, but the experience of using mysms varies greatly depending on what kind of phone you're using. I tested mysms on an iPhone and an Android phone. We did not have a Windows phone available for testing, but the company says that many of the restrictions set on the iPhone by Apple's limitations also exist for Windows Phone users.
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