Back in the good old days, when it used to cost money to print and distribute books, people took a lot of time working on their information before it went to print.

After all, it's pretty embarrasing to see the printing press whizzing off 10,000 copies of a book - with the same spelling mistake on every front cover.

Now, on the Web, such a mistake could be corrected in seconds. A typo on a site homepage can be removed at virtually no cost. Since the information source is created at the moment the reader requests it (from the server), you only have to worry about the few people who saw it before you noticed it.

But this change in economics - from the variable costs of printing books, to the low fixed costs of running a web server - has meant that the quality of information takes second place to the quantity you can produce. It's no longer worth it to spend a lot of time checking what you publish, when it would be better spent creating new material.

The real issue comes about when we detach the person hosting the information from the creators altogether. The web (and its forums, blogs, social bookmarking, etc) allow people with no more than 5 minutes in a cybercafe to contribute to the Web. You don't have to research, check your facts, then publish. You just type, and it's there for everyone to see.

This is great - if the intention is to produce quantity of information. It's not so good if you want to ensure the accuracy of things published. When you open up publishing to everyone - without filtering - you end up getting the good with the bad.

Visit any web forum on a controversial subject, and you will quickly find the blurring of opinion with fact. People don't reference their sources, as their debates are more about winning the argument - rather than discovering the truth.

And now that most web users are also publishers, this is the kind of information you stumble upon when researching through Google. Rather than fact-checked articles and reports, you get snippets of people's viewpoints. People suggest courses of actions that they've actually never tried, and advise people on medical issues that put their lives at risk.

Many Universities still ban their students from referencing Wikipedia, pointing out that it is not an original source - and is open to manipulation (although the editors usually catch major errors, many minor ones still get through). In the outside world, though, people log on to the web without such preferences. They are not so sceptical about what they read. And, without the regulations of professional advise, they can't sue "the internet" when things go wrong.

Does this mean that we should shut the Web down, and start again with a peer-review system? Of course not. The web has flourished because it allows anyone to publish, not in spite of this freedom.

But in this age of the citizen-publisher, we all have to be more vigilant about what we read online... and be very careful who we listen to. We have to learn to cross-reference things, to understand people's motives for suggesting things and to generally be on guard.

In time, we all need to learn how to be good information publishers. Until that time, we're going to spend a lot of time filtering the good from the bad.