Windows Phone 7 developers were given access to a Beta Refresh of the Windows Phone 7 Mango OS build earlier today so they could continue development and testing of their apps.  This is build 7712 which is supposedly very close to the RTM build that was announced yesterday.  

When asked why Microsoft was not providing developers the RTM build Cliff Simpkins provided this reply on the Windows Phone Developer Blog:

For the folks wondering why we’re not providing the ‘RTM’ version, there are two main reasons. First, the phone OS and the tools are two equal parts of the developer toolkit that correspond to one another. When we took this snapshot for the refresh, we took the latest RC drops of the tools and the corresponding OS version. Second, what we are providing is a genuine release candidate build, with enough code checked in and APIs locked down that this OS is close enough to RTM that, as a developer, it’s more than capable to see you through the upcoming RC drop of the tools and app submission. It’s important to remember that until the phone and mobile operator portion of Mango is complete, you’re still using a pre-release on your retail phone – no matter the MS build. Until that time, enjoy developing and cruising around on build 7712 – it’s a sweet ride, to be sure. :)

Although there have apparently been many bug fixes added to this beta refresh since the first version came out to developers last month one of the biggest features added is the incorporation of Twitter into the phone.  I do not believe it is 100% integration at this point but it is likely very close.

After updating my phone to the 7712 build, which went very quick and smoothly compared to the issues I had with the original beta Mango install on my LG Quantum, I went to the accounts page and added my Twitter account to the phone.

If you head to the People Hub at this point you will see your main Twitter list as part of the People What’s New page.  Depending on how many people you follow on Twitter this can be a lot of updates.  You can filter what you see here by selecting the all accounts link under what’s new on that page and show either all accounts, or just Twitter, Hotmail or Facebook.  I am opting to just follow Facebook here for now.  If the Twitter filtering option ever adds the ability to select a Twitter List then I will definitely be back here to track my Twitter timeline.

If you want to see tweets that mention you, those sent with your username and the @ sign, then you want to use the Me tile.  On this you will see the latest tweets you have sent on the profile page and if you slide over to the notifications page you will see any tweets listed that mention you along with Facebook and Hotmail items.  This is the part of Windows Phone 7 Mango where you can send tweets out yourself.  Just tap on post a message on the profile page and select the account you want to post to and type your entry. The number of characters you have used and what is remaining for your 140 character tweet will pop up at 111 at the bottom of the compose box.

If you use Facebook Places to check in to various locations you can opt to post those check-ins to Twitter at the same time. 

Pictures can also be shared via Twitter with this new build and they they are posted using Windows Live SkyDrive as the storage medium.  The default Twitter URL shortener is used to share the link when it is tweeted out to your followers.

IE9 is now the default browser on this Mango Build so if your running it check out the IE9 Mobile Test Drive website.  The performance on the phone with IE9 is quite spectacular.  Check out this video of the IE9 Test Drive Fish Tank.  Sorry about the blurriness.  The Flip Ultra HD does not do good up close video but I think you can still see the speed of the rendering.

I still have more to explore in this build and will let you know what I discover.  If your running this new version of Mango and have discovered some new things please let us know in the comments.