you still need to install Antivirus software on Mac most people believe Macs are immune to viruses this is not the case they are less common but are vary much out there
This is misinformation at best. I just watched a segment on the news last night where a supposed "IT professional" laughed at the notion that Mac OS X was less susceptible to viruses than Windows and even went so far to claim that Mac OS X was
more susceptible to viruses because people don't use anti-virus programs on their Macs.
Macs are, indeed, less susceptible to viruses. Mac OS X is built atop one of the strongest and most robust operating systems in the world, and that operating system has nearly 40 years of security and hardening behind it. There isn't a single, viable virus for Mac OS X that is "in the wild" today. Most of the security threats you hear about are not actually viruses, but
trojans -- which require specific user actions in order to cause any harm.
A good test to see if something is a virus or trojan is to do this:
1) Turn on your computer.
2) Immediately walk away from your computer.
During that time, if your computer became infected with something, that would probably be a virus (given the computer was not already infected when you turned it on). The difference between a virus and a trojan is that a virus is able to (and specifically designed to) infect your computer
without any human interaction whatsoever. A trojan, on the other hand, requires the user to take very deliberate steps in order to "help" it install itself -- this could be presented as fake dialog boxes that ask you to input a password, click a button, or otherwise interact with the computer and/or operating system in order to give the trojan "permission" to install itself.
Viruses needn't ask permission. Trojans do. Viruses exploit errors, "back doors" and other security shortcomings to
automatically install themselves, surreptitiously, and without user knowledge. Trojans have to knock on the front door, pretend to be a girl scout with cookies so that you let them in, then quickly change into demon-beings that run rampant amongst your house.
Since Mac OS X is built atop the world's strongest and most secure OS architecture (UNIX), the only way a trojan or virus has any hope is to exploit Apple-based portions of the OS... namely, the GUI, Quicktime, Java, Safari, etc. Because of this, and because of Mac OS X's and UNIX's user permissions system, the only thing that's viable is a trojan -- not a virus.
This is not to say that viruses will never exist for Mac OS X -- they may! -- but they're going to have to be able to affect FreeBSD UNIX first, more than likely, and that's going to be a tough nut to crack for them... they've been trying, mostly unsuccessfully, for 40 years now.
Windows users bear the responsibility of protecting themselves. While it's certainly a nice gesture to say, "I have anti-virus on my Mac -- not because I'm under any kind of threat, but just so I don't accidentally pass on any Windows-based viruses to my friends," it's not your position to be altruistic and overly helpful in this sense. If my neighbor consistently leaves his front door open at night, I'm not going to take it upon myself to continually watch for intruders -- at some point, he's going to have to do this himself.
I recommend absolutely no anti-virus software for your Mac -- as long as you keep it completely up-to-date with Software Update, I'd be willing to bet my pinky finger that you couldn't get infected with a Mac OS X
virus no matter how hard you tried. Anti-virus software on a Mac will only do the two following things:
1) Protect your Windows brethren from becoming infected with a virus that you accidentally pass on, more than likely coming from forwarded emails or the like (your Mac will never pass on a virus without your permission to a Windows computer)
2) Slow down your Mac
