Stehle,
Have you cleared history and cookies via the tools, options, privacy, show cookies, clear all cookies, process?
When you close your browser (firefore) does a pop-up window come up asking you to confirm deleting history and cookies come up? I would delete everything from a surfing session using the tools, options, always clear my privacy data, ask me before clearing privacy data, settings, option.
I don't leave cookies, passwords, history in my browser history while I sleep

I can help setting your privacy setting so you can clear that, I think.
Sometimes history and cookies can save you time next time you plan on visiting a site.
Often, the cookie is used to track your surfing habits and provide you with interesting ads based on your surfing history, including sites you go to when shopping, paying bills.
I guess getting ads for energy saving products and "meet singles in your area" would be important when using the internet to pay your electric bill
Cookies and IP addresses are ways the web advertising companies (A lot of them are LEGIT) keep track of what is popular. You want to be popular, right?
Did you know that search engines are smart enough to associate your various entries in forum posts to identify a person's first and last name, state, sometimes city, and email address and target you for important ads and promotions you would hate to miss out on?
Like extracting names from things like johnsonjoseph99? in Cincinnati?
A search engine has NO PROBLEM associating that through every internet service licensed to do business in Ohio and waiting for a match. Even if it takes 64000 tries. The one that doesn't net them a "undeliverable" message is Joe. Joe will now get important information on meeting really reaaly sweet young ladies that would like to do really really cool things to his johnson, which by the way has been recently enhanced with the pills he bought from the e-mails he got on that topic.
Cookies are just so darn helpful.
Rocket, IP address 131.99.99.oh-shit