rel=canonical is a way to tell Google which the primary version of a URL is. It's handy if you have substantially the same content on several URLs - perhaps because you have a shopping site and allow users to sort a list of products by price or name, and this is reflected in the URL.

Adding this meta tag used to work only on the same domain.

But Google has announced today that it will support rel=canonical across domains - ie if you have the same content on more than one website, you can tell Google which is the main version you'd like it to index.

Ever wonder which of the Express's obsessions it's most obsessed by? Here's what the archive search tells us ...

If Murdoch wants to put the Sunday Times or the Sun behind a paywall but still wanted Google to index his content, he would have to join first-click free.

If he decides the Sun is really the Wapping News Journal and joins Google Scholar, then the rules would be different. He could have his content indexed without having to let anyone see it unless they paid a subscription. On top of which, Google would give his content priority if was the original source of a story.

For some off reason, ITV released the X factor results for each round in a PDF. I'm an SEO whore, so here they are in HTML ..

It's the pre-budget report today. Business Link, the government's advice service for businesses, is bidding on the term "pre budget report" in google's adverts.

Maybe we could repair the budget deficit by wasting less money driving traffic to a site that doesn't have any information on?

Shownar is a BBC site that tracks the online buzz around the broadcaster's shows. Despite being paid for out of the licence fee, it's pulling the wool over bloggers' eyes by making out that, if you link to it, it will link back - but it's nofollowing the links.
The BBC should either make them normal links - or be much more transparent about its "you link to us and we'll link to you" statement.

Google's rolling out personalised search to everyone, even if you're not signed in. It means that: The results you see aren't what everyone else sees, making SEO analysis that much harder.

And If you do a rubbish job of selling your site (either through the title in the results, or in terms of what they see when they click through) to people who commonly perform the same search, your site is going to drop out of their results. Gulp.

UK national newspaper Twitter accounts are continuing to grow - but the rate is getting slower and slower, according to the latest figures for the 129 accounts I'm tracking. November to December growth was just 6.6%, down from 17% earlier in the year.

This roundup of what some paywalls look like when you hit them illustrates that publishers - and Johnston Press in particular - need to massively improve the way they promote the benefits of subscribing ...

Google's new layout (only on google.com, not .co.uk, so far) has increased the importance of local SEO about a million times. Check out these two screenshots of a search for "St Albans offices" - one on google.com and one on google.co.uk.

Google's got a new layout on its way (not yet visible in the UK) which means a new google sprite (the one image it uses to render all its icons). Here's the new one and the old one.

Like most bloggers, I'm plagued by comment spam - but I've found a good way to spot the spammers: Backtype. It shows you comments on blogs that link to a specific URL.

I've really begun to loathe Twitter's new retweet function. Here's why:
Pictures of people I don't follow, unclear menu options and not being able to see who is retweeting stuff.

The Information Commissioner's Office webform is a joke - the validation is awful. Also, they seem to have confused the internet with email.

New Media Age is experimenting with first click free - which always raises a troubling question for me. How do you persuade your users that you're "confident this content ... is worth paying for" - when it transpires you give it away for free to every tom, dick or harry who arrives via Google? Just what are we paying for?

Search Google for I'm a Celebrity, which starts today, and ITV's site is top - as it should be. Search Google for I'm a Celebrity 2009, however, and the ITV site is only fourth - behind Digital Spy, the Metro and Free Betting Online.

I'm a Celebrity 2009 results
I'm a Celebrity 2009 results

Even worse, the Free Betting site is an affiliate site with a massively optimised page designed to get I'm a Celebrity traffic - that links out to free sports (not TV-related) betting sites.

As well as the Sun misjudging its readers' mood over Gordon Brown's handwritten letter, Daily Mail readers also seem to be sympathetic to the Prime Minister.

The best rated comments on its story are those with sympathy for the PM. The worst rated are mostly criticising him.

The Daily Mail has been lambasting football clubs for playing games without wearing "the poppy that symbolises respect for the nation's heroes".

But where's its poppy, eh? Other papers are wearing poppies - why is the Mail a poppy refusenik newspaper. SHAME.

The Sun is running a pretty despicable campaign against Gordon Brown - and the majority of its readers don't agree with the paper's stance if its website comments are anything to go by.

While idly checking Google's results for a Jan Moir search, I noticed that a top-10 result for the Angry Mob's site - a post from September called Jan Moir: I'm thinking she's a piece of sh*t - has been toned down in Google's results.

So does Google edit out swear words for popular searches? Or has it done a manual hack on this one post to spare Jan's blushes? The evidence is leaning towards the latter ...