Counting the clicks and misses

Websites can find it tricky to count mouse clicks

By Mark Ward BBC News Online technology correspondent

Websites are looking at ways of getting a more accurate picture of how many people click on an internet link.

At the moment, internet sites have very different ways of counting the numbers of people visiting them.

Often activity counted as a single user at one site would be tallied several times at another.

This can make it difficult for advertisers to work out where to spend their money or for businesses to compare themselves with rivals.

Big log

Standardised ways of counting clicks and users have been agreed and are administered by ABC Electronic, the digital arm of the Audit Bureau of Circulation that collects readership figures for thousands of magazines.

But not everyone uses the standard measures yet.

You cannot get anywhere near as much detail in the print world

Richard Foan, ABCe

"There are still a lot of sites that are not audited, but we have a lot more signed up than we did a year or two ago," said Richard Foan, managing director of ABC Electronic.

"Those that have signed up, and even those that haven't, recognise the need to analyse all this data far more effectively," he said.

When web servers generate the webpages that users see, they typically collect information about what they have done, and where they have sent it, in a central log file.

But the vast amount of data in this file is not always an accurate guide of the numbers visiting a website.

"There are all kinds of problems with log files," said Mark Wilding of website analysis firm Intellitracker.

Web spiders

Search sites such as Google and Altavista find out what is on the web by using automated software programs that interrogate and catalogue every site on the web.

Some sites like The Guardian audit users every month

However, the computers responding to these requests do not know that another machine is asking for the pages and counts them as legitimate users.

Proxy servers that story popular web pages to speed up their delivery to customers of net service providers can also skew figures because the central site holding the information is not involved in handing over the information.

There are other ways that visitor numbers are distorted.

"A large site can employ a lot of people and they can spend a lot of time looking at their own site and that can affect their viewing figures," said Mr Wilding.

Visitor numbers

Before now many companies have been reluctant to sign up for audits because of the time, expense they take and because they could often show that fewer people are visiting a site than its owners previously thought.

Typically log files over-estimate the number of visitors to a site by 30%.

Web analysis companies such as Intellitracker, WhiteCross and Net Genesis collect and clean-up data on behalf of customers to help with auditing.

The whole point about the internet is that it can be tracked to the last detail and there's nothing like that offline

Mark Wilding, Intellitracker

Gradually, said Mr Foan, common ways of counting clicks were proving their use and helping sites survive.

He said companies looked at the figures after carrying out a marketing campaign to see if what they did had any effect. Some website managers use the figures to show their boss how successful a site is becoming.

Mr Foan added that many media buyers who place adverts on websites were also using the statistics to rank sites and decide where to spend their money.

But, he said, many sites have realised that the main reason for carrying out an audit is because of the insight it gives into a website's user population.

"You cannot get anywhere near as much detail in the print world," said Mr Foan.

Some sites such as The Guardian newspaper and Yahoo now audit monthly to get snapshots of how their site is developing.

"The whole point about the internet is that it can be tracked to the last detail and there's nothing like that offline," said Mr Wilding of Intellitracker.

"Offline there are no guarantees about readers at all," he said.