This well kept secret surfaced just recently. All Apple devices running iOS 7 have a pretty darn well hidden Easter egg. Just follow this step-by-step instructions carefully and the very first Mac OS version 1 will appear on your iPhone or iPad. How freaking awesome is that?
You got a .rar file and you don't how to open it, some one asked you to send him "a rar file" or you just need a good archiving software? Download and install WinRAR.
If you are a Skype user, it maybe disruptive for you that the program is shown in taskbar, although you don't need it at the moment. I will show you how to remove it from the taskbar.
Gmail offers you a new way of organizing your emails in tabs. You have a tab for you personal conversations, a tab for social media related emails, promotional emails with offers and a couple of more tabs.
If you want to make a clean install of the new OS X Mavericks or even the older versions of Mac OS X, than I strongly suggest you to create a bootable OS X key or a drive.