Fri Feb 25, 2011 2:33am EST

* FY operating profit up 39 pct to 56.6 mln stg
* Average monthly spend per advertiser up 23 pct
* Site traffic up 17 pct

LONDON, Feb 25 (Reuters) - Rightmove (RMV.L), Britain's most visited property website, posted a 39 percent rise in full-year operating profit as homebuyers and sellers turn to the internet to navigate a challenging property market.

The company, which has been established on the web for 10 years, reported underlying operating profit of 56.6 million pounds ($91.2 million) on 26 percent higher revenue of 81.6 million pounds on Friday.
Estate agents spent on average 379 pounds a months on the site, up from 308 pounds in 2009, as they opted for higher profile display advertising.

Rightmove, which is already used by the vast majority of Britain's estate agents, said the number of advertisers rose 2 percent to just over 18,000, while traffic on its site rose 17 percent to 7.6 billion page impressions.

(Reporting by Paul Sandle, Editing by Mark Potter)