Lion is the next version of Mac OS X that will be released later this year. Apple released a developer preview today and it included a surprise inside — Mac OS X Lion Server. Mac OS X Lion Server is now a core feature of OS X Lion and included for the time being at no extra cost. You will be able to selectively setup your Mac as either a regular Mac OS X client or as a Server during the OS installation.
Once your Mac is transformed into a server you will be able to perform local or remote administration and implement server features that include: configuration of users and groups, file sharing, contacts, chat, Time Machine, VPN, mail, calendaring, push notifications, web, and wikipedia — all services that run under Mac OS X Lion Server.
The new twist to all this is support for the Apple iPad. This is accomplished via the Profile Manager which provides simplified setup and management of Macs running OS X Lion and all iOS based devices (iPhone, iPad, and iPod touch). All of this is leveraged off of existing network directory services, but even more important is the ability to push updates to these mobile devices over the air. Those updates are pushed out using Apple Push Notification services.