You are trying to install or open an app that didn't come from the Mac App Store but you got a message saying App can't be opened because it is from an unidentified developer. This is how you bypass it.
For those who just got the new LG flagship Android powered smartphone LG G2 and are not quite sure where to start, here is the very basic what to do after I turn the phone on tutorial.
Errors on the hard disk on your Mac OS X computer can be the cause why the computer doesn't run as fast as it used to. Let me show you how to check and repair the errors on a disk drive.
If you don't have installed program for editing PDF documents on your computer, then you can use web application PDFescape which allows you to edit your documents in your browser.
A real useful tutorial for the beginners where you will learn how to do a simple zoom in effect on a random text and them zoom out of it again in Adobe Premiere CS5.