Google's dominance of the search engine market is gradually being clawed back by old-hands Yahoo and MSN, according to a recent study.

A survey of 2,000 people by Keynote Systems revealed that while Google easily retains the top spot and provides the best service, an increasing number of people are listing Yahoo and MSN as their primary search engine.

According to Keynote, 20 per cent more people now list Yahoo as their main search engine, compared to the same survey six months ago. MSN boasts a 30 per cent increase - something the survey attributed to its decision to separate its sponsored search results from non-sponsored Web results.

Three-quarters of those surveyed said they would only use one search engine, but 50 per cent said they would change search engines if they were unhappy with their current one.

As ever with such surveys though, there is a questionmark over Keynote's impartiality. The research was conducted independently, the company claimed, but it admitted that some of the search engines companies featured in the survey were also its clients.

A Keynote spokesman refused to say which search engines were paying customers however. Nevertheless, it doesn't require a degree in logic or history to hazard a guess that since Microsoft comes out smelling of roses, that Redmond may be up to its old tricks again.

Additional reporting by Brendan Sullivan, IDG News Service