The rise of the 'citizen journalist' has given many professional hacks cause for concern. (As one who is retaining his amateur status in order to compete in the 2012 Olympics, I have maintained my customary sang froid.) The blogosphere is here to stay, and it's where many people get their news. But libel laws remain.

Even if your online diary is read only by you and your mum, or your forum takes the form of a stilted conversation with yourself, your publication is subject to exactly the same legal constraints as the Times or PC Advisor. And it's published, every day, for all the world to see. So here, for the uninitiated and unwary, is the 'PCA guide to staying out of trouble on the web'. You can't afford not to read it. (Slag it off and I'll sue.)

1. If you can't prove it, don't write it.

You may have seen Mummy kissing Santa Claus with your very eyes, but if you've got no proof then Father C's got you over a barrel. Oh, and tapes are inadmissable. Photos can be faked.

Look, just be very sure before you publish. Then make sure again. If you're accused of libel you have to prove your own innocence. And that's tough for most of us at the best of times.

2. Be specific.

Want to point out that Matt Egan is a boring old windbag with a head like a potato? Feel free, but make sure you refer explicitly to PC Advisor-staffer Matt, aged 28(ish), from south west London. Otherwise my great uncle Matt (who tragically suffers from a very rare form of potato-head disease) could sue your ass.

This is why the red-tops always give names and towns for people they mention. It's also why we have to be doubly careful to get product names correct.

3. Don't hide behind 'allegedly'.

Doesn't work. Neither does attributing quotes to someone else. If something appears on your blog or website – even if it is a forum posting – and the person or company it refers to is defamed, you're in trouble. Take it down immediately.

If you've heard that a rumour isn't true, spread the good news. But don't repeat the allegation. Incidentally, defamation is damage to reputation – in all forms. It's easier to do than it is to apologise for.

4. Be picture perfect.

As your site becomes more sophistacated, you may wish to illustrate your thoughts. The same rules apply. Recently, the Sindie came a cropper when it used a shot posed by a model to illustrate a story about kids with Asbos. D'oh.

Use only pictures taken by yourself or ones which you have permission to publish. And if you are illustrating 'drunk' or 'evil', you'd better make sure the person you picture is happy for you to do so. Or an evil drunk. If all else fails make sure 'Picture posed by model' is clearly stated.

5. A year is a long time in publishing.

You can be sued for libel for up to one year after you publish. This is stringent enough in print, but online you 'republish' every day. And once something has been on the internet, it will forever exist, somewhere in the dark recesses of the net.

So before you dash off a casual defamation of a rival team on your pub footie website, be aware that, although the opposition isn't online right now, it may well be in the future. This happened to a team in the league I play (badly) in, and they ended up getting the chop from the local FA. Worse still, we lost the points we got for beating them earlier in the season. No crime is victimless...

Happy (and safe) publishing.