The MySQL Server from Oracle comes in a two different flavours: Community Edition and Enterprise Edition. The first one is under the GPLv2 license and the later is under the GPLv2 or Commercial license.
The Enterprise Edition was always available from https://enterprise.mysql.com (which now has an expired SSL certificate) under the GPLv2 license. This download page was restricted to paying customers. Since the Enterprise downloads were moved to https://edelivery.oracle.com the downloads are available for everyone (as long as it's not restricted by export regulations and accept the trial license agreement). The license is now 'Commercial'. The download be named V24071-01.zip or something like that, which is annoying. The latest version for the Enterprise release on edelivery is 5.5.8 while the latest Community version is 5.5.11. Previously there were two enterprise releases: Advanced (With partitioning) and Professional (Without partitioning). If you use https://support.oracle.com you can search for patch 12332498 which claims to contain MySQL Advanced Server 5.5.11. The download is named 'p12332498_55_Linux-x86-64.zip' which is a bit better than the filenames which edelivery generates.
Oracle does provide RPM's and Generic Tarballs, but no Debian packages. And Debian/Ubuntu is used a lot, even in bigger companies. There is no yum repository available for MySQL Enterprise, so there a no auto updates and easy installs. There is an official and public yum repository available but that's only for Oracle Enterprise Linux and Oracle VM. And their Solaris repository also doesn't have the latest MySQL versions (Only 5.0 and 5.1).
The MySQL Enterprise Subscription also contains MySQL Enterprise Monitor, MySQL Enterprise Backup and MySQL Workbench. There were RPM's available for the MySQL Enterprise Agent, but it turn's out that that was a mistake. The official way is to use the installer (Yes unattended installation is possible). But no update via yum/apt or any other method. Just run de agent update installer on every machine.
For the Community version there is also no YUM or APT repository and that might be one of the reasons why every one sticks to the old versions which are shipped with their Linux distribution of choice. It would be much easier to install packages with a hard dependency on mysql together with the latest official mysql if there were deb packages available. For more info about when not to use yum/apt read Shlomi Noach's blogpost.
There are deb's for MySQL Workbench available and there are also RPM's, but unfortunately the dependencies are not complete RHEL6.
Percona is a good example about how it should be done. Their repositories are accessible via APT and YUM. There are no repositories for Solaris and Windows yet, but I don't know if anyone is really interested in that.
How do most folks keep there mysql servers updated? How do you monitor if there are any security related updates available? Do you use an in house YUM/APT/WSUS repository?