I've explained the ins and outs of MotoBlur extensively in my reviews of the Cliq and the Devour so I'll only summarize the main points here. Like its brother, the Cliq XT runs Android 1.5 (the Devour, on the other hand, runs 1.6) with MotoBlur running over that.
MotoBlur essentially aggregates all of your social networks and delivers them within a seamless interface. It supports contact syncing across social networks, a unified inbox for your various e-mail accounts, and live widgets for social networking. Another cool feature is its ability to track your phone via assisted GPS if the device gets lost. You can wipe it remotely, and all of your information will be saved on the MotoBlur's servers.
Aesthetically, MotoBlur feels a bit cluttered. Icons and font don't have the pop or the prettiness of the iPhone OS or WebOS alternatives. But if you're an avid social networker and you find the out-of-box Android interface a bit uninspiring (as many people do), MotoBlur makes a solid alternative.
Like all Android phones, the Cliq XT gives you access to the many useful Google applications (Gmail, Google Maps with Navigation, YouTube, Google Search, and so on). You can set up and sync your Yahoo account with the device and get full Outlook sync support, too.
The Android browser supports Flash Lite, enabling you to view certain video content and Websites that likewise support that content. Full Flash Player 10.1 for Android is coming later this year.