What is the likelihood of my internet transmissions being spied on in this situation?
If I go to the public library and use the public wireless internet there, and I have that wireless network set to "public network" on my computer, and I go to My eBay, which is encrypted, and I buy something, and pay for it with PayPal, which is also encrypted, what is the likelihood that anyone at the public library could intercept or spy on the internet activity that I just described? How would that be done?
A lot of this will depend on your knowledge of "Certificates" & which ones (if any) you have accepted while at the WiFi location;
What ‘flavor’ of encryption (if any) is used on the WiFi (not related to the SSL PayPal connection);
If you have scanned for "Firesheep" cookie grabber by using "BlackSheep";
Do you have a comprehensive understanding of bullet-proof passwords and have deployed a strategy that covers all ‘log-in’s"?
Can anyone observe your physical keyboard or screen (including any overhead cameras)?
Is your PC in fact completely spyware free?
If these topics sound like gibberish, then do NOT use a public WiFi for delicate commerce related transactions.
This does not cover the extensive subject of NSA "Prism"; only the local environment.