But observers also say there are several key differences between the situation Google finds itself in today and the one Microsoft fought in the 1990s.
The first is that Google so far remains committed to open platforms, which are information systems that do not lock consumers into a single product or a single vendor's technology.
The second is that Google and Microsoft act as constraints on each others' activities, whereas Microsoft faced no such competition at the height of its market power.
One Google competitor which declined to be named also notes that Microsoft is successful in several major markets, whereas Google remains vulnerable because, with 97 per cent of its revenue derived from search, it is yet to diversify successfully.
"They're struggling to get that second piece," the rival says.
But, if nothing else, Google's cash reserves, reputation for innovation and roster of 20,000 rigorously selected employees have many predicting it is only a matter of time before the company grabs a strong position in a market other than search.
That would be a development that Foer says could become a major cause for concern, particularly if Google further cements its position - through mobile search, Google Books, Google Talk and more - as the dominant gateway to much of the world's information.
He cites the view, inspired by the global financial crisis, that companies should not become "too big to fail".
Already some people argue that a major systems outage at Google could have serious repercussions on the web. It is a charge Google rejects.
Foer says: "It's not size that we're worried about, it's complexity leading to systemic risks such that we can't afford to allow a company to fail.
"The problem is, if a company is situated in such a way that it's failure would be politically unacceptable, what are we going to do about it?
"And the answer to that is something we haven't figured out yet."
THREE LEGAL CASES
Google is being sued over its alleged abuse of keywords in searches
* Moët Hennessy-Louis Vuitton has a long-running suit over Google's selling of internet search keywords that are also trademarked brandnames. In a practice known as bait and click, rival firms can buy search terms such as Louis Vuitton and direct web surfers to their own page instead of the brand holder's.
* US computer repairer Rescuecom has sued Google, alleging that the internet giant infringed its trademark by selling the repairer's name to rival firms as a search keyword. On April 3, a US appeals court reinstated Rescuecom's suit after it was initially dismissed in 2006.
* In February, search engine operator TradeComet.com launched legal action against Google. TradeComet claimed that Google raised the rates it charged for keywords once it realised the company was a rival. Google said it doesn't think there's merit to the suit.
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