First we were employees, plain and simple, writes Lucy Kellaway. Then we were knowledge workers. After that came "Brand Me" and the notion that we were all CEOs of Me, Inc.

Now our taste for hyperbole in describing our place in the economic order has become still more rarefied: what every modern worker aspires to be is a thought leader.

The blame for this latest craze rests with the editor of Strategy and Business, a management magazine. In 1994, he needed a name for a new interview slot and came up with Thought Leader. Back then, it seemed a forgivably pompous title for the pompous thoughts of management gurus. Thirteen years on, it has come to be a much less forgivable name for any old fool in possession of an ego and a blog.

The title offends for three reasons, and pomposity is the least of them. It is inappropriately Orwellian: in free societies, thoughts can be provoked or stimulated or gathered - but not led.

Worse still, no one seems quite sure what "thought leader" means. You might think that to qualify as a thought leader, you needed to have a thought and be able to influence others with it. Yet when the term is used, there is no sign of any thinking or leading going on at all.

This week, the Thought Leader Index 2007is published by a new "communications and thought leadership consultancy" called Ledbury Group. It went around asking chief executives, trade union leaders, editors to name their favourite thought leaders. The result, surely, gives an up-to-date snapshot of what the term actually means.

Top of the list is Google. This presents the first challenge to my definition: Google has no thoughts and no brain with which to have them as it is a company. It might be brilliantly successful, but is it a thought leader? It has only led my thoughts to the extent that I no longer retain any knowledge in my head, I just look everything up on its website instead.

The next favourite thought-leading business is Apple. Again, I don't get it. Apple leads my wallet and my taste for gorgeous sleek gadgets, but not my thoughts. I am oddly forgiving each time my iPod breaks and hurry to the Apple store to replace it with a more glamorous model, but that's as far as it goes.

You could say both Goldman Sachs and McKinsey (respectively eighth and ninth place) suggest thoughts of a kind. Goldman's thought is "we are richer than you" and McKinsey's is "we are brainier than you". Both companies also transmit a more subliminal thought - "we know something you don't, so stay close to us". Yet this is more a veiled threat than an idea, and so doesn't really count.

Of the top 10 companies, only the British retailer John Lewis (fourth) has a proper, original thought and that is "we are owned by our employees". But on closer inspection that isn't a thought. It's a business model.

From this list of thought-leading companies, the concept seems to boil down to this: "thought leader" is simply a new and unhelpful way of saying successful.

The list of the top thought-leading individuals is just as baffling. The number one slot goes to Al Gore. This shows that to be considered a thought leader, you don't need one of your own: it's fine to take someone else's. Gore's contribution was saying it very loudly, with some PowerPoint slides.

Bill Gates follows. I would classify him as a former thought leader. His was the idea that there should be a PC on every desk in every home, and very influential it was, too. But as for any other specific thought he has had, I can't think of one.

By contrast, David Cameron has a very clear thought: "I want to be prime minister". But the snag is that it's too early to know if the rest of Britain wants it too.

Gordon Brown fittingly makes it onto the list at number 10. Though if I were him my main thought would be: "Why the hell have I been ranked behind Sir Terry Leahy of Tesco, whose only thought is to build more and more hideous supermarkets?"

I am left none the wiser by the Thought Leader Index, so for elucidation I've gone back to Google. For just $109, you can buy a book called How to Be a Thought Leader, written by nine leading thought leaders. In the blurb, I couldn't see anything about thinking at all. It is all about "passion, relevance and reach". A more helpful website offers the following definition: "A thought leader is a person or company that actively promotes and discusses ideas that are relevant to their peer base." If this is all it is, being a thought leader is a total doddle. But it also raises the more interesting question of why companies or people feel there is something so great about it. Surely the job of business leaders is to lead businesses, not to have original thoughts. The second may sometimes be a route to the first, but equally it may not be.

An analogy with my (somewhat inarticulate) sons is apt. By the above definition, both are thought leaders as they actively promote and discuss World of Warcraft, a lethal and addictive computer game favoured by their peers.

But what's so good about that? Indeed, I wish they'd stop leading thoughts and get on with their homework.

- (Financial Times service)