Basically, the update allows for Twitter replies to show up on a tweet and The KIN Loop now shows pictures from picture links directly in the shell without having to open the browser.
If you are one of the few owning a KIN, the updates can be accessed through the KIN's over-the-air update system. Speculation on why Microsoft continues to update a dead device range from testing out Twitter functionality that may land on Windows Phone 7 to testing OTA updates.
Then again, these updates may have simply been close to being finished when the plug was pulled and Microsoft didn't want to leave any loose ends. Regardless of the reasoning it's nice to see Microsoft lending support to those who continue to use the KIN.