While there are many things possible, there is also the extremly unlikly. If the OP wants to post a link to a public website and uses a public network, she is safe. Unless its a site about WMDs. :-) Or terrorism thats on a national watch list. And if you use different public networks at random, tracking becomes almost impossible except for the use of a LOT of federal resources.
Well, I'll admit it's not likely for mongers like us, but I assure you that LE is willing and able to search logs on MANY different public wifi networks, and that, over time, they're able to match those MAC addresses to a person that they want to track. There is also always the possibility of a "honeypot" network. LE sets up a network near Starbucks and gives free wifi to everyone willing to connect, which also allows them to see every bit of network traffic.
It's not easy to stay truly anonymous if you're connecting to someone else's network. Originally Posted by Crock