Dean Anderson, who owns and runs an ISP in Boston, explained the basics best, so I want to share his tips with you.
EBay, the FTC, Citibank, and consumer-advocacy groups advise to make sure you're using a secure server connection. Dean comments on the wisdom of that tip and holes that can be exploited by the con artists.
"When you connect to a secure Web site, you can examine the SSL Certificate for the site, usually by clicking on the 'lock' symbol on many browsers," he says. "People should learn how to do this and make it a habit of doing so when they connect to secure sites, so they recognize when something changes.
"Unfortunately, like other components of scams, the certificate might have a similar-sounding name. You think you've got (e.g., PayPal.com), but you got paypal-business.com. The certificate (we assume for argument) really does belong to an entity called paypal-business.com, but is paypal-business.com the same as PayPal? You don't know.
"The best thing to do is start from (e.g.) paypal.com from your account statement, etc., and examine the site certificate. Then you have a good chance that it's not spoofed. But it is only a chance, as it could still be spoofed in various ways. There are lots of scenarios for this, but here's one: Your computer could be infected with a virus which installed a Web proxy, then the attacker sends you a message to go update your stuff. You type in paypal.com, but your infected browser goes to the fake site instead. When you try to view the certificate, your infected browser shows you the real certificate information. You can't easily know this didn't happen. But examining the certificate is a good practice.