At the beginning of the year Mojang started dropping hints of their plan to switch from a name based accounts system to a universally unique identifier (UUID) based accounts system, ultimately moving towards allowing people to change their Minecraft name. With much of Minecraft currently relying on a name based accounts system (bans, whitelist, ops to name a few) along with plugins using names to keep track of players (permissions, ownership, protections), this change has a high potential to break both plugins and servers if server admins and developers are not prepared for it. At the time of writing, Mojang have said they're planning to enable name changing around the time Minecraft 1.8 is released and with Minecraft 1.8 slated to release in May, the window for preparations is quickly closing.
What is a UUID?
A Universally Unique IDentifier is a fairly long series of hexadecimal numbers commonly used in software to uniquely identify something. With Minecraft, Mojang is planning to use UUIDs to identify player accounts, with each Mojang account tied to a UUID. For example: Notch's account now has the UUID "069a79f4-44e9-4726-a5be-fca90e38aaf5".
What this means for us?
Because i am unaware of a lot of our plugins future with this update I cannot reveal the future to a full extent the only thing i can tell you is that you should NOT change your minecraft username, although it maybe tempting if you do so, you may loose something of extreme value. The main plugins causing conerns are lockette and iconomy, every other plugin seems to be prepared however these two could go down, which means looking for alternatives, I STRONGLY advise that people start using their faction banks to store their money as there could be a very unexpected iconomy drop.
DO NOT CHANGE YOUR MINECRAFT USERNAME!