Yes, when you buy gas, regardless how much, part of your money goes to countries like Saudi Arabia.
Saudi Arabia uses that money to spread the word of wahabbism, whose followers include Bin-Laden. This money also allowes Saudis and others to make "donations" to certain groups, and eventually this money gets into hands of terrorists who use it to buy weapons and train.
Now that doesn't make you a terrorist any more than buying Chinese goods makes you a communist sympathiser. But you are indirectly supporting terrorism, and should be aware of it. Now if someone would make the same connection between pot and terrorism I would appreciate it. The administration was just asking for this when they came out with these lame ads.