Everything you send out first goes to your ISP then to wherever. Same with what you receive, which gets to them just before getting to you. Hell yeah they can find out your credit card #. They can find out what you spoke with your girlfriend during last night's icq convo. Depending on country/zone regulations they keep logs about EVERYTHING you do online. When I say deppending on country don't get me wrong.
US has such laws. Canada does. All UE countries do. Sorry to bear bad news folks, but anyhow cisco routers keep the logs for about 6 months by default. So, if they get complaints about you, better be sure they're gonna see what you did. And rest asured, in theese countries, there's no dificulty for the authorities to convince your ISP to share the logs. Hell, most ISPs don't even need a warrent, all they need is a written request.
Read this too:
http://news.bbc.co.uk/2/hi/uk_news/3106158.stm
This post proves to me, once again, how little knowledge of what anonimity is about realy is out there. I can bet that 90% of the people on this board are convinced that browsing tru a proxy or better yet tru proxy chains means their compleeeeeeeeetely anonimous, safe, being able to do whatever they want and no one knowing who they really are.
Also I am aware that most of the people using proxies don't really need them, it's just some extra caution that makes them feel better, and they're prolly not doing anything illegal...
