In Washington lawmakers have been asking some tough questions, and today an EU data protection committee has called on Google to "pause" the new policy while its implications are considered.

But the most vociferous - and expensive - campaign against the policy has come from Microsoft, another technology firm that makes extensive use of personal data.

The company took out big adverts in American newspapers this week, suggesting that Google was collecting more and more data about its users in order to make ever more cash from advertisers.

This was followed up with a YouTube video featuring "Gmail Man", who serves a woman with an advert for an ointment after reading her email and spotting the keywords "burning" and "sensation".

Google, surprise surprise, is furious about this campaign, and claims that Microsoft is telling untruths about its policies while being less than frank about its own. And a quick scan of Microsoft's own privacy policy for its Bing search engine does turn up this:

"We may use search query data for the purpose of personalizing the ads we display to you as you use our services or those of our advertising partners."

Microsoft says, though, that its Hotmail service does not examine keywords for targeted advertising in the way that Gmail does, and does not use data from one service to target advertising in another. Google responds by pointing out that Gmail has been doing the same thing since 2004 and has always made it clear.

Google feels that on a key issue for its industry like privacy, the web giants should speak to the regulators with a united voice rather than making trouble for each other.

That may be unrealistic. Microsoft feels that Google has no right to complain about hostile adverts, given the money it has poured into its own "Go Google" ads recently. And, having suffered in the regulatory spotlight for years, it appears to be enjoying the fact that Google has now become the target on issues ranging from privacy to competition.

I can't help noticing that a PR firm called Burson Marsteller sends me an email every now and then about some incident showing Google in a bad light. They are, of course, employed by Microsoft.

It may be unseemly, but the war of words between Microsoft and Google looks certain to provide plenty of entertainment for onlookers. And, for all the peace and love streaming out of Google's Californian headquarters, they are not above a bit of fighting talk themselves.

"My advice to them is focus on your own business," a source at the firm told me, pointing out that Microsoft didn't really have an online business to speak of right now.

How much we are deemed to be worth is what will determine the value of the business when the shares are priced. Facebook, like Google, is an advertising business and one that has introduced a radical new way of reaching consumers. With Google it was via our searches, with Facebook it's our likes, dislikes and all the other data that we contribute freely to the site.

Ask anyone about adverts on Facebook and they are likely to tell you that they never notice them, and are sure they have no impact on their purchasing decisions. They are quite likely to say the same about the ads served up by Google, yet the search firm's clients are happily handing over billions of dollars, confident that this is the way to reach their customers

On a visit to a London digital marketing agency yesterday, I got a glimpse of how powerful a platform Facebook can be for advertisers. I-Spy demonstrated how they could funnel into Facebook's data to target a precise group of people - say, 25-40-year-olds in the Reading area, looking for jobs in the technology sector.

The agency, which used to send nearly all of its clients' marketing budgets in Google's direction, is now putting about 10% on Facebook, and expects that to grow. Jim Brigden, I-Spy's CEO, was enthusiastic about what the social network could offer in terms of targeting, but cautious about whether it would ever be as useful as Google.

He explained that Google delivered customers who were already looking for something, while Facebook might be better for engaging with consumers and letting them know about a brand. "It won't work for everything," he said. "You wouldn't try to sell funerals or financial services." But his clients, from a recruitment agency to the makers of Spam (the real thing, not that stuff in your inbox) were very happy with the results so far.

What we will find out when the IPO papers are filed is just how much revenue this kind of advertising is earning for Facebook, and how rapidly that is growing. Then Wall Street will have to decide how to price the shares. Last week they were trading privately at a valuation of $80bn, and there is talk of the price tag climbing to $100bn or above.

That figure looks ridiculous for a business with much to prove, but optimists will say that there was similar scepticism about Google's IPO in 2004. The search firm went on to show that it was worth a whole lot more than the value at which it floated.

Whatever the price, the Facebook IPO will generate eye-watering sums for investment banks, lawyers, and of course Mark Zuckerberg and other owners of a slice of the business. Then the really difficult bit starts - showing that the Facebook audience really is a valuable resource, willing to be targeted with more and more advertising. In other words, it is up to you and your Facebook friends.

Let me explain how that strategy works. Its fundamental principle is that Apple will only communicate with the outside world on its terms and to its timetable, and that means at exquisitely stage-managed events in California.

So Apple has never attended exhibitions like the Consumer Electronics Show or Europe's IFA, and a few years ago the firm even severed links with the annual Macworld conference because it did not want to have to fit in with someone else's schedule.

Apple has long been a company where all power is centralised in Cupertino, California, and after Steve Jobs' return from exile to what had become a leaky organisation, he made sure that everyone understood that talking to the media or any outsider without his permission was a sacking offence.

For a while Jobs himself did give the occasional interview, but certainly for the past five years it has been virtually impossible for journalists to ask direct questions to anyone from Apple, except at product launches.

And even when there is an opportunity to talk, the company's PR minders are determined not to let reporters go "off topic" - just look at what happens in this 2007 interview when Benjamin Cohen from Channel 4 News asks the wrong question.

I joked once to a group of Apple PR people that it would be easier to get into North Korea than to get proper access to the firm. They laughed nervously and mentioned that there was a popular T-shirt at the company store with the slogan "I work for Apple in Cupertino, That's all I can tell you..."

But, hey, I hear you say, the company is free to conduct itself with the media any way it chooses, and it's worked pretty well so far. And that is absolutely true. But what happens when American customers and politicians start reading about what seem to be the appalling conditions in which your products are made?

There have been a number of exposes over the past 18 months of working conditions at Apple's Chinese factories.

The most startling I've heard came not from a journalist but an actor, Mike Daisey. His monologue telling of how an obsession with all things Apple ended up with him visiting China and finding workers, some apparently as young as 13, putting in 15-hour shifts, was performed recently on the radio programme This American Life.

More seriously for Apple, the New York Times has run a series of articles over the past week examining why America's most successful company can't manufacture its products in the United States, and then taking a closer look at conditions at its suppliers.

Read his interview with Reuters

To be fair to Apple, it has for some years been publishing annual reports detailing the inspections it carries out at its suppliers, and this year it has released a list naming the companies.

But the latest audit shows that at 93 factories, workers put in more than the 60-hour weekly limit prescribed by the American firm, and a third of all the plants inspected did not have sufficient measures to prevent employees suffering occupational injuries.

Now, calls for consumers to start boycotting iPhones or iPads are unlikely to have much of an impact. After all, just about every major electronics brand manufactures in China, and it is far from clear that if you buy a rival phone or tablet it will have been made under better conditions.

It seems clear too that, however miserable the work in the vast factories making every kind of gadget, it is lifting millions of Chinese out of rural poverty.

But in an election year, US politicians may have some tough questions about why a company with $100bn in the bank cannot afford to invest a little more of it at home, creating much needed jobs.

Which brings us back to Apple's PR strategy. Tim Cook, the man who took over from Steve Jobs, told staff in an internal email:

"We are defined by our values. Unfortunately some people are questioning Apple's values today... We care about every worker in our worldwide supply chain... Any suggestion that we don't care is patently false and offensive to us."

But so far Mr Cook has shown no sign of wanting to be any more open with the press or public about this or any other issue than his predecessor. The next time he speaks in public will probably be at the launch of the iPad 3.

But he may find that, once he's extolled the new device's awesomeness, he faces questions about whether the way it was manufactured accords with Apple's values.

Apple has been in touch, seeking to correct the impression I give in this post that there has been nothing said in public about conditions at its suppliers in China. The company pointed me towards two interviews given by Tim Cook in recent days to Reuters and the Wall Street Journal about this very issue.

Perhaps a subtle shift in Apple's PR strategy under its new leader is already under way.

For BBC Radio 4's Today programme, Rory gets a "personal privacy audit" and investigates whether there's a need for more regulation on the sharing of personal data online.