
It is common these days to be using web services on a wireless network or from a phone. When you are in a public place, there is the possible danger of someone eavesdropping on what you are doing. (See Gizmo's discussion of the perils.) If you use the ordinary unencrypted HTTP protocol, almost anyone could be an uninvited observer of your web activities. There is even a simple extension for Firefox called Firesheep that uses a packet sniffer to intercept unencrypted cookies.
When using sites with personal information, the more secure encrypted protocol HTTPS should be used. HTTPS connections can be a little slower on some connections but the...