One of the more annoying facets of the Internet is the ability to spread online hoaxes and urban legends. These did die off in popularity at one point, but now seem to be enjoying a resurgence with the ability to spread them through Facebook and Twitter.

They are annoying in that while usually not harmful, they contribute to filling bandwidth with things that are simply not true. I said “usually” since you should keep in mind the point that some are indeed meant to be harmful.

What I find most annoying is that they often play on the good will of the targets to pass on false information in hopes of helping their friends avoid some particular hazard.

Some examples include the periodic post you will see on Facebook asking you to sign an online petition to prevent Facebook charging for its services, or to repost a long block of legalese that will supposedly prevent Facebook from allowing people to use your pictures and posts because they now are a publicly traded company.

Neither of these is true. Facebook has publicly stated on many occasions that it has no plans to charge fees to users. Really, they don’t have to, since they make a decent amount money selling advertising. The legal post has no meaning, since the Facebook user agreement you accept by using Facebook allows them the right to sell your posts or pictures, and furthermore, the long block of legalese has no legal power.

These are examples of hoaxes that do not have any more effect than cluttering your news feed. Others are a bit more insidious in nature.

You will often see the call to avoid using Swiffer WetJet cleaner because it leaves harmful chemicals on your floors that will poison your pets. There really isn’t any difference between using it or any other cleaner in this regard. But, people dutifully pass on this vital information to all of their friends. The best assumption is that this was originally started by one of Swiffer’s competitors to encourage you to use their product instead.

The same is true of the famous “Don’t use Tylenol cold medication because it contains PPA [PhenylPropanolAmine], which causes strokes.” I’ve seen this one recently, despite the fact that PPA has not been used in North America since 2000. Again, assume that one of Tylenol’s competitors spreads this.

Other examples are the offer of free gift cards on Facebook. Many companies have been targeted in this way, including Tim Hortons and McDonald’s. And, don’t forget the many offers of free iPads. These hoaxes exist for many reasons, such as competitors wanting to frustrate you with these companies when they won’t redeem the free gifts or to obtain information about you when you apply for the free gift card.

A good rule of thumb is, if it is not a local company that you can directly contact and check with, do not click on links for free offers. If it’s free, it’s too good to be true. If it’s too good to be true, it almost always isn’t.

Some other things to watch are emails from friends or posts warning of viruses. One of the first Internet hoaxes was the Good Times virus, which would do incredibly horrible things to your computer. The actual “virus” part of this was filling the inboxes of your friends with warnings, since there was no such thing.

Others virus warnings may tell you to delete a certain file, which is the definite indicator of having a particular virus. This is harmful, since you are usually asked to delete a vital system file, which will make your computer fail to work.

There is also the “dying child” hoax, which asks you to send emails and some amount of money be donated to research some illness. All of these are fakes and are designed to determine valid email addresses for later mass mailings.

So, be careful of what you see on the Internet. Ask yourself how credible a story or an offer really is. [If it’s a hoax, a quick Google search with the key words from the email will often yield stories from people who have already been fooled–Ed.] If you are asked to click on a link for something free or spread the news to everyone you care about, chances are high that someone, usually with best intentions, is pulling the wool over your eyes.

Doug Rutherford teaches computer networking and security for Yukon College and three post-secondary educational institutions in British Columbia.