A couple of years ago the big sites were working on a wing and a prayer

Mark Saxby

But it has not turned out like that at all.

A widely quoted study by Zona Research found that it takes only eight seconds for people to lose patience with a website.

Other studies have shown that many web shoppers, up to 65% in one report, fill their virtual shopping carts with goods but abandon them before they get to the cash till.

"A couple of years ago the big sites were working on a wing and a prayer, no-one was asking what's unusual about our user base," said Mark Saxby of web monitoring and measuring company White Cross.

Now many companies are turning to sophisticated monitoring and tracking technology in a bid to turn browsers into buyers. Using cookies and logs generated by web servers, companies have access to lots of statistics about what visitors are up to.

Watching the web users

Without this deeper understanding of who is visiting their site, the time they spend on each page, the routes they take through the site and the information being served up to them there is little chance that companies will make a website pay its way, said Mr Saxby.

Stay on for eight seconds and you could win a prize

"It is all about acquisition and retention," he said. "It is about keeping people on the site and giving them what they want."

Often just gathering and analysing this information reveals a lot about the way a site is, or isn't, working.

One unnamed website thought it was getting a huge response to an ad campaign but a look at the weblogs showed that visitor to the particular webpage were getting error messages. The high number of hits was caused by people reloading the page in a vain attempt to reach the special offer.

The data can also help companies tailor their site around the way that people use particular pages. There is no point putting banner ads on pages that people spend no time on.

It also reveals clusters of visitors who appear during TV advert breaks, or after the end of a popular TV show. Many websites tailor webpages for these audiences.

The analysis of "clickstreams", the route that people take through a site, can also provoke changes to how a webpage is designed. This can reveal neglected corners of a site that might be worth eliminating or even making easier to find if the people that do visit them spend money once they get there.

"Dynamically changing pages as people go through the site does take a lot of cash," said Mr Saxby, "which is why only a few people are doing it."

Bigger business

BA: Closely monitoring everything that its users do

The hard work that companies have to undertake does not stop at the website.

Before now many websites have stood alone and had few links into the computer systems businesses use to keep their main business running.

The lack of links between a companies web shop and its warehouse stock watching system led to many companies taking orders for goods that they did not have on the shelves.

But tying together a website and all the other computer systems in the wider business beyond is no easy task.

Thomas Boyle of web reliability firm Segue estimates that most websites can support only a handful of so-called concurrent users before they crash.

"Concurrent" means people consulting a database or making a purchase at the same time rather than just looking at a simple webpage.

"Performance for a web front end is a huge issue," said Mr Boyle. Sites that suffer long-lasting outages can see their stock price slump and can cost them a lot in compensation.

Breaking the web

In the past AOL has had to pay millions of dollars in rebates to users who were unable to access e-mail and other services during outages.

Without good testing of companies can find that their website can support only tens of users rather than the tens of thousands that it should.

The close linking of website and wider business systems can also have unforseen effects.

Some banks have found that cash machine networks slow down in the morning when lots of people are using the website to query their accounts, or check out special offers.

"It used to be the case that you went to the doctor when you were sick," said Mr Boyle. "Now we have moved on and you can find out what you need to do to maintain your health based on your life style, and we're starting to apply the same to websites."

"We can ask: 'Where does it break right now?'" he said.