Zoopla’s revenue and profits have moved sharply upwards as it both charges more to agents and attracts more agent advertisers. Traffic to the site has also increased, by 37% over the last year.

This morning, announcing its half year results for the six months to March 31, Zoopla said average revenue per member per month was £301, compared with £251 for the same period a year ago.

It had 19,239 advertisers, up from 17,803. There were on average 39.9m monthly visits to Zoopla, up from 29m.

However, the number of property listings barely changed over the year – 1,097,000 at March 31, compared with 1,064,000 on the same date last year.

Revenues for the half year stood at £38.3m, up from £30.3m, with adjusted earnings before all tax and costs (EBITDA) at £18.7m compared with £14.8m.

Zoopla also said that mobile devices now account for over half of the monthly site visits, and that Zoopla agents are “benefiting from higher volumes of enquiries and as a result are increasingly purchasing additional products over and above the standard subscription packages”.

It said the most popular additional marketing products are premium listings, appraisal boosters, and area sponsorships.

Zoopla’s property valuations – controversial with agents –  are also being well used, at an average of over four per minute.

Zoopla founder and chief executive Alex Chesterman said: “We are delighted with the strong growth in our audience and engagement levels over the first half of this year as more and more consumers rely on our websites and mobile apps to both search for properties and research the property market.

“We remain focused on building a sustainable and profitable business and continuing to deliver on our mission of providing the most useful property resources for consumers and being the most effective partner for property professionals across the UK.

“We are pleased that we have continued to deliver even greater value to our members whilst group revenues have grown and as a result we were able to pay an interim dividend to our shareholders of £14m for the period.”

Nothing in today’s announcement referred to a flotation on the stock market, which could value the business – majority owned by the Daily Mail – at £1bn.