I see an unusual trend, when I log into my gmail account often multiple times a day, I get a lot of spams, usually in the order of 100-200 per day. If I don’t login for a week, I maybe get 20-30 a day.
So, either the spammers know via cookies (flash or standard) or somehow can see the online status of my gmail. I have my account hidden from outsiders and no one can chat with me if they’re not on my friends list. I also have no malware on my machine and I carefully monitor network activity. I also keep track of website scripts and whitelist semi-trusted sites so some may have gotten through.
Is it always a good idea to dump all of your firefox history after you close a session of browsing? Then open up ccleaner to get rid of flash cookies? I think these two things would minimize spam to a degree.