What privacy and security risks am I exposing myself to when I connect my MacBook to an open insecure wireless network?
Are there any risks that are worse or better when compared to a Windows PC that's connected to an insecure wireless network?
The primary concern is that any HTTP communications (and other non-secured communications) could be intercepted, including cookies, which often contain your login information. Note that secure communications (HTTPS) have other methods to keep your information safe, so financial communications are usually safe.
The secondary concern is that your Mac can be directly attaqued by any other computer within a 50 m radius. If your Mac doesn't have its firewall on, then this attack may lead to some file access (through guest account), and some remote control (through Apple Remote Desktop, VNC or more secret system vulnerabilities).
This security risk exists equally whether you are using OS X, Windows, Linux, or any other operating system, and there are no additional risks (nor less) on any platform.
Just because we're rocking a very secure OS, doesn't mean viruses, malware and the like can't happen. Be vigilant, all the time. It is a misconception that you are not prone to virii. Basically: all the same risks as if you connected a PC laptop to an insecure wireless network. Just with a lower probability of getting attacked.
the simples trick is: 1-someone is looking over your shoulder what you typing (in public place) so DO NOT type, use copy/paste for password (stored previously in a document !) so they do not see which keys you are using. 2- Turn on Firewall, use only httpS in your browser ect... 3-What kind of Public WiFi are you connecting to? 3.1- one where you just jump on (fully open). 3.2 Anyone with logon info can join (bars, hotels, ect (still risky). 3.3 Connecting to a public router (with many others) but you have your unique/personal log in (only router owner/administrator can screw you).