When you have been exploring the menus on your Apple Mac, you may have checked out About This Mac on the Apple menu in the top left corner. It tells you the version of OS X you are running, which processor you have, the amount of memory that is installed and its type, and the startup disk.
There are two buttons, Software Update and More Info, which we will come to in a minutes. First we will look at a hidden feature... Just under the OS X heading is the version in light grey text and it'll say something like 'Version 10.9". Click the 10.9 (or whatever number it says on your Mac) to see something different, then click again to see something new, and again. It cycles through the OS X version number, the build number and the serial number. It could be useful to know.
There's a Software Update button that launches Software Update (no surprise there), and it is the same as running Software Update on the Apple menu. These days software updates are through the Mac Store app, so you'll see that open.
There is also a More Info button and this starts a System Information app. It displays lots of technical details about the Apple Mac and the software that is installed. It's not something you will need to run every day, but occasionally you might find it useful.
There are three options on the View menu: Mini Profile, Basic Profile and Full Profile. Select the Full Profile to see everything. Select Hardware in the left pane and you'll see brief details about the Mac like the processor name, Mac model name and identifier, and so on.
Expand the Hardware section if it's not already expanded and select Diagnostics on the left. It shows the result of the Power On Self Test, which is a check the Mac performs when it is switched on. It should say 'Passed' and if it doesn't then there's something wrong with your Mac. Select Bluetooth to see some useful information, such as the folder other devices are allowed to browse. It should be ~/Public, which means your Public folder and for security reasons you don't want Bluetooth devices like other people's mobile phones to have full access to the system. You can also see the folder other Bluetooth devices can download to and whether you'll be prompted for file transfers. For safety's sake, it's best if you are notified.
Select Memory on the left and it will show you the number of memory modules that are installed, the number of sockets, and the type and speed of the RAM. This is important if you want to upgrade the memory because it tells you exactly what type you need to buy - the same type and speed, but a higher capacity.
Select Power and if you have an Apple MacBook you can see the batteryu information. Look at the Full charge capacity entry to see how healthy the battery is. It should be over 5000 and if it's less than 3000 you should think about getting a new battery. The cycle count tells you how many times the battery has been fully charged and then depleted. If the full charge capacity is low and the cycle count is low then Apple will replace the battery for free. That's worth knowing!
Poke around and you'll find other useful information in System Profiler. Some of it is a bit geeky and probably not useful, but some of it is.
Affilate links follow...