If you log in from your office, the Web site operator may be able to see that someone from your companys network paid them a visit. If you log in from your home, using a dial-up connection to an ISP, your connection will probably just be a face in the crowd. In my experience, while Web site operators take an interest in who is logging in, a visit from the opposition is nothing unexpected. Sites that are driven by advertising have an imperative to find out as much as they can about their visitors, so that they can show potential advertisers what sort of audience drops by. But its not necessarily a Big Brother situation most mainstream sites also have privacy policies, which protect your personal details from the marketing brigade.
Many Web sites provide help for beginners.
My favourite newbie sites are Learn the Net , Internet for Beginners and Newbie No More , but there are plenty more. Your ISPs Web site is also a good port of call.