If a tree falls in a forest and there is no one to record the event on YouTube, does it still make a sound? This is the philosophical mindbender for the silicon generation. It was announced this week, with some fanfare, that an hour's worth of YouTube video is uploaded every second. That's an awful lot of talking dogs.

Actually, I quite like the talking dogs. I'm not sure I'd want to employ one, though, and I can't say I'm cheered by news that employers are increasingly ignoring the classic CV and choosing job candidates on the basis of their "online profile". Which is as much as to say that it's no longer what you think or know, or even what you have done that counts; the modern metric of success is how much noise you make in cyberspace.

The blogging and the tweeting and the Facebooking, the endless Googling – all those things your teenagers do as naturally as breathing, things your slow, saurian brain has dismissed as "arsing about on the computer when you should be revising" – turn out to be important life skills.

I can see that, to prospective employers, one's online activity says more about the individual than a professed love of hill-walking; maybe it's the awful, empirical proof of the cyber-footprint that frightens me, the idea that you are the sum, not of experience sifted and sorted in the traditional manner (a process once known as "growing up"), but of every fleeting 2am interest.

It frightens me even more that, as of 1 March, when Google rolls out its new, improved tracking technology, information itself will be sorted according to user-profile, with search queries "tailored" to interests already expressed on online forums such as Google+, Gmail and social networks.

Apart from ordinary concerns about privacy and targeted advertising – the latter is surely driving the initiative – this seems to me a sinister and curiously mind-shrinking refinement. If, for example, you type in "race relations" and have previously Googled "UKIP", does the search engine register your "interest" in immigration policies and lead you straight to websites dealing in Nazi memorabilia?

It can be argued that established information vectors, such as radio, TV and, ahem, newspapers, have traditionally reflected and reinforced the prejudices of their adherents, but Google's ad hominem add-on makes a hollow mockery of the broad and impartial database that has, until now, been the defining virtue of the World Wide Web.

Concern is rehearsed about the effect of the internet on how we think – scatter-gun intellects, attention spans of gnats etc. I'm willing to see the other side of the argument – clearing out the well-stocked brain in the interests of faster, more efficient processing. But I balk at a system where the brain is stocked with (and jobs secured on the strength of) the last hilarious video I forwarded to my friends of a fat man falling in mud. "I link therefore I am"? No, thanks. Or at least, not yet.