Usage of Rightmove's property web site has been at or close to record levels in the period since the beginning of July, with August proving to be the site's second busiest month ever.The number of advertisers on the Rightmove website at the end of September stood at 18,100, up 2.5% since the start of the year. Changes to pricing are progressing according to plan, the company said.The number of page impressions in the July-September period was around 16% higher than in the corresponding period of last year.Estate agency and lettings membership rose to 14,850 by the end of September, a 5% increase from the start of the year.All the membership growth is coming from estate agents rather than rental only agents. Average revenue per agent (ARPA) during the third quarter was ahead of the average for the first half of the year, reflecting both the full impact of price rises to membership fees implemented between January and the start of May, and further growth in adoption of Rightmove's advertising products.As for newly built homes, the number of new developments coming to market from volume house builders was stable during the period though there was a further small decline from Housing Associations.The board said it is confident of meeting expectations for the current year. "On the assumption that housing market conditions continue to be challenging (i.e. with housing transactions running at around half the levels of a normal market) but do not substantially worsen, the board expects to achieve significant organic growth in 2011," the company said.