User privacy worries, market dominance concerns and, most recently, a spat with eBay resulting in the online auction site pulling its ads from Google; taken together they make for a bad week for the Californian internet leviathan.

Privacy concern is the issue that might knock Google from its perch, and last week's report by Privacy International didn't do the "don't be evil" search company any favours by using phrases like "possibly deceptive" and "entrenched hostility to privacy" regarding its consumer policies.

One of Google's huge advantages over competitors is the way that it remembers what you, one of its users, has searched for before, and which search results you click on. This allows the algorithms that power the search engine to tailor its results to what it 'thinks' you may be looking for.

Theoretically this data could also be used to profile your political allegiance, religious beliefs, sexual orientation or habits based on internet use. Google says it needs to store search requests for a variety of legitimate reasons such as legal data retention obligations and responding to requests to assist police investigations.

Personalised search information was, until last week, stored for up to two years by Google but after considering a letter from EU officials requesting an explanation of this time scale, Google's privacy counsel Peter Fleischer said the company would reduce the maximum time the US company holds personally identifiable data to 18 months.

Google's swift response to the concerns of EU data protection experts will be welcomed by some observers, but it makes clear Google recognises the threat to the relationship of trust it has with its 1.1bn users.

"Google ain't going nowhere and it doesn't have too much to worry about at the moment unless it makes a complete faux pas like accidentally releasing all of its North American email addresses, " said Ovum senior analyst Mike Davis. "Even then, it wouldn't lose all of its [search] business as it is the default search engine in millions of browsers."

Market dominance is another criticism Google will be keen to avoid. In a column for the Financial Times last week, former deputy chair of Britain's Competition Commission, Denise Kingsmill, suggested a market inquiry into Google in the wake of its acquisition of online ad giant DoubleClick. Kingsmill wrote that businesses seeking an alternative to Google "will now lack a meaningful choice".

"Microsoft was dumped on by the competition authorities in the EU and the US, and you know you've made it when your business has had an anti-trust warning, " considered Davis.

Perhaps the most telling development last week was Ebay's decision to pull its ads from Google's US websites.

Ebay, Google's largest single advertising customer, was piqued because Google had planned a party celebrating its Checkout service . . . a rival to Ebay's online payment service PayPal . . . the same evening Ebay was holding its Ebay Live convention in Boston.

Most analysts reckoned that the two internet giants were too dependent on each other to remain estranged for too long, but the row marks a growing willingness of some of the technology world's stars to confront Google.