TripAdvisor has seen the total number of user generated reviews on its network of sites increase by 50% in less than a year to reach a new high of 15 million.

The US-based, Expedia-owned review giant said the leap of five million reviews from June 2007 to March 2008 came as its overall traffic – including those of its network of other sites – reached 25 million monthly unique users.

The traffic levels have been boosted by major acquisitions in recent months including the UK-based HolidayWatchdog.

TripAdvisor said it planned to continue its aggressive growth strategy of acquiring other media-based companies as well growing organically.

Co-founder and chief executive Steve Kaufer added: “When we started out in 2000 I never imagined we would achieve this level of growth.

“We began with hotel reviews and we now also feature candid photos, videos, favourite lists, travel wikis, forums and more, to help travellers around the world plan the perfect trip.”