Changes, changes, changes. Somehow, Mixx is able to make changes 10 times faster than any other major social media site on the Internet. All of the changes (except one) look to improve the functionality and user experience immensely.
On their blog, they explain these changes in detail. As with any major change to a website, my natural inclination is to a) test it inside and out, looking for flaws, and, b) try to break it.