Never give personal information especially financial to a website unless you see the padlock icon. It is usually a good habit to never follow links in email you receive. To make sure you are on the correct website open up a browser window and navigate to the website where you want to conduct business. This is most important when exchanging personal information or transacting business such as buying items, Internet banking or bill paying.
If you follow these rules, on-line shopping is actually safer than a shopping center or crowed mall.