If you like I'll provide the link to the ZD Net blogs where the Mac Defender virus/Trojan is discussed ad nauseum.
Pixie, you're computer (OS X) has always been vulnerable. It's just that now the bad guys are starting to refocus on the Mac
(at one time there were no Windows viri, all viri was for the Apple, but that was a long, LONG time ago and the subject for another discussion).
I would say right click, choose open in new tab or window ... guess you can't do that.
/ pixie, address to all
The set search options to open in new tab/window in Google, I used that for the longest time then it decided the option wouldn't stay set between sessions.
About visiting websites that are inherently not trustworthy, the bad guys crack a trustworthy site and plant data the spider will find and will create a link in a search result to a page on the cracked site the the site owner won't see (not exactly accurate but works for this explanation). That hidden page contains redirection code, and I believe those are the strange addresses you see running through your bar.
I believe it was Symantec that had a good write up on this.
McAffee is notoriously crappy, Symantec is a little better, I've heard good things about BitDefender but it's annoying, and I'm not sure any of those work on OS x.
Sophos has a Mac anti-viri, and I just remembered, there was a patch released for (I think it was) Safari to prevent the installation of Mac Defender,
I wouldn't say anyone is infected BUT I wouldn't say your NOT infected either.
What I learned way back when I got my first firewall (Zone alarm, looooong time ago), I got all these alerts from pings and port scans. Then it was pointed out to me it isnt the alerts I was seeing that should worry me, it's the alert I'm not seeing ...
Same with viri, it's the one you DON'T see, the one that ISN'T detected that is going to get you.