5 things you should definitely avoid doing online

If you walk around London staring open-mouthed at the tall buildings and various landmarks, the resident low-lives will mark you out right away. Pickpockets may try for your wallet, streetside vendors may offer great deals on "genuine" Rolexes – out of a suitcase, of course. Even if you're smart enough not to get taken, you're better off keeping a low profile. The same is true in the online world.

There are some things you should just never, ever do, and we’re going to list five big no-no’s here.

Never put your email address in a comment

Don't put your email address in comments on blog posts. Don't put it in Facebook comments. You may have set Facebook for privacy, but your friends haven't. Don't include the address in plain text on your own website; use an image. Spammers send web crawlers to harvest exposed email addresses and fill your Inbox with ads for Canadian drugs and Russian girls.

Never respond to spam

Angry at the spammers? Don't fire off an irate missive. Don't reply with "REMOVE" in the subject. All this does is verify for them that your address is owned by a person who actively uses it. That makes it much more valuable when they sell their list to other spammers, and can lead to a whole host of other issues. For more details on this, see: The reasons why you should never respond to spam email.

Got an unsolicited email promising you a free iPad, a vacation in Belize, or something else tempting? Resist that temptation! Clicking that link won't get you the prize, but it might well recruit your computer into the latest botnet army. Sure, your antivirus or security suite will probably keep you safe. So in the best case, you get… nothing.

Never share your password

Okay, this may sound too simple, too obvious a tip to point out; and yet I've seen people do it. "Hey, can I use your [fill in the blank] account?" Sure, it's a good friend asking, but will this person safeguard your security the way you would yourself? Maybe you don't really care about that particular account, but are you sure you haven't used that same password on one, two, or twenty other sites? Sharing is good, in general, but not password sharing.

Never do your banking at the coffee shop

Banking over the public Wi-Fi at a coffee shop or Internet café is a seriously bad idea. These networks can be ridiculously insecure. The guy at the next table could be using Firesheep to capture your online session. The sinister café owner could be tracking every packet that passes through the network. Save your online financial transactions for times when you can connect to a secure network.

These tips won't guarantee your total online safety, but they're a good start. Follow them and you won't look like a clueless yokel in the big virtual city of the net…