The words we hammer into internet search engines are as true a reflection of our inner thoughts and interests as the outside world will ever get to see. We're not prompted by pollsters or gently guided by external forces; if our field of interest happens to be Nazi memorabilia or midget porn, we're happy to tell a search engine. Anyone who has a blog and has been bored enough to check their statistics will be aware of the bizarre search terms that people type in before stumbling across their pages; my friend Emma recently noticed searches for "mackerel painting" and "gulag lips of inpenetrability" that had inexplicably directed people to her blog about life in Brussels. We treat the search box as something private, the contents of which are known only to us and the search engine.

But it's not that private, of course, because it's run by a company. As a result, the likes of Google get as close to the pulse of our collective interests as it's possible to get, and as such they're the envy of politicians, journalists and anyone whose job it is to sell us stuff. We get to see some of this data every December when the end-of-year round-ups are published, and one of these, the 10th Google Zeitgeist report, shows us the fastest-rising and -falling search terms over the past year. In 2001, Nostradamus and the World Trade Center were in the ascendancy, with Pokemon and the Sydney Olympics slumping; this year, it's Chatroulette and the iPad that have captured the spirit of the year, while bush fires and Susan Boyle are very much yesterday's news.

The sheer size and digital savvy of the USA makes the data set rather States-centric; seventh in the list is Trinidadian hip-hop artiste Nicki Minaj (pictured), who is vaguely known over here to tabloid readers for the size of her bum, but over the Atlantic she's had seven singles simultaneously in the Top 100 and is a much bigger deal. But it's the frivolity of our interests that irks cultural commentators. Where are Julian Assange and WikiLeaks in the list, they'll ask. Why have we ascribed such importance to cupcakes and guacamole in 2010? How can Lady Gaga possibly rank above the Gulf oil spill? But the search data doesn't lie; that's what we're interested in. The news agenda will never dovetail perfectly with the stuff we scour the net for, and for that we can perhaps be thankful. The oil disaster did head up Twitter's top trends list for 2010, however, indicating that the much-maligned service might have a bit more substance than its detractors would suggest. Of course, searches for our modern human preoccupations – sex, conspiracy theories, reality television – will remain static year-on-year, but rapidly changing interests provide valuable indicators of our behaviour. The recently launched Google Price Index is just one way that the search giant can use data to show economic trends; it could also easily analyse, say, the intensity of job searches being done in certain areas. On a more mundane level, a digital intelligence company called Webtrends managed to predict the outcome of The X Factor early on Sunday evening, simply by analysing stuff that the British public had posted online. Every time we hit that return key, we reveal something small about ourselves – but we also collectively reveal more substantial information about ourselves as human beings. It's not always pretty but, unlike many surveys, it's pretty honest.

Beware of big numbers this Christmas. That's the warning that should probably be given to anyone heading into town to buy items of audio-visual gear for their nearest and dearest; a blog post at Gizmodo this week has reiterated the long-established fact that consumers tend to buy gadgets whose technical specifications sound more complicated and are more superficially impressive, rather than whether they're actually better. When data gathered by engineers is presented to a marketing department, it kicks off this baffling digital free-for-all: details of frequency response, dynamic range, contrast ratio, colour gamut, viewing angle – barely any of which gives a true indication of the unit's performance, no matter what a sales assistant might tell you. It's so endemic within the industry that technology companies can't really not do it; abandoning jargon would be like L'Oréal going big on the campaign slogan "Makes you smell nice". So seek the opinions of friends or experts you trust, and don't be distracted by yellow stickers with big numbers on them.