You have just seen in action. If you are confident you downloaded a safe copy of the program, you can tell your Mac to 'trust' that program and let it past the gate. • Right click on the icon • Select Open • Read the dialog and agree or disagree to let that program run The linked article above goes into much detail on GateKeeper and I would scan it and review the steps above. If you find a lot of software you need triggers the warning, you could relax the settings, but I prefer to keep them at the defaults as I like to know when new code runs on my Mac.
As with any other piece of software you have to trust the developers. What you can do is to validate your download against a checksum. I suppose that you've downloaded OOo_3.3.0_MacOS_x86_install_sv.dmg. Its MD5 checksum is 869e4b23022a7d3ea33a5c (from ). Open Terminal and type either md5 ~/Downloads/OOo_3.3.0_MacOS_x86_install_sv.dmg or md5sum ~/Downloads/OOo_3.3.0_MacOS_x86_install_sv.dmg (not sure of the top off my head). If the number you get coincides with the MD5 checksum above your download is OK.
I have a brilliant Macbook Air that has Microsoft Office and oggy and the cockroaches jack in a box games minecraft 1.7.2 cracked download no survey Chromium OS for MacBook Air Released, Here is How to Install on Your. 
Microsoft Offering Free Windows 7 Product keys for Windows 7 Beta chevy. Fifa 2005 exe.
– Nov 20 '12 at 9:00.