It's a wonderful concept. You record every click, every search phrase, every Website visit and every e-mail ever received. You use client-side surveillance to capture the tiniest twitch of the mouse and the most subtle hover behaviour. You use this information to serve up just the right offer at just the right time. The result? More sales, less marketing spend and happier customers. What could be better?

It might be better if you could raise revenue while lowering costs and improving customer satisfaction on a regular basis.

Can you build a giant datawarehouse and arithmetically deduce the one best offer to make to each and every Website visitor? Sure. But be prepared for a lightening of the wallet. There are many other ways to make more sales at significantly less cost and keep your customers happier in the bargain.

I’ve been asked to address these issues at the Knexus Community round table in London on 16th November. Senior executives from the UK’s major corporations, including financial, are getting wise to the business of customer personalisation and want to know how it can help their business.

Well, consider this and think of your own online customers:

Amazon knows every book I have purchased online since 1996. They can certainly turn that into persuasive content to e-mail or display on their site when I show up. And they do - if I reach for it. I have to click to check my recommendations rather than get them via e-mail or simply see a home page plastered with them. Why? Because Amazon is very good about ROI. They like to go after low-hanging fruit.

Amazon knows that customers who bought "Harry Potter and the Half-Blood Prince" also bought "Ark Angel: Bk. 6" by Anthony Horowitz. Anybody interested in the former might well be interested in the latter. Does this increase sales? Oh yes. And a quick peek at my credit card bills will testify to that fact.

Amazon also knows unequivocally what I like because I told them. I said I wanted to know whenever John Grisham or Neal Stephenson publish a new book. What's the technical difficulty on a scale of 1 to 10? About 1.5. The ROI? Amazon won't tell. But they will get that certain gleam in their eyes.

How does the customer feel about this? Fulfilled. I like reading. I like being in the know. I like being ahead of the curve. Satisfaction on a scale of 1 to 10? 11.

But how would I feel if Amazon offered me nothing but Grisham stories and Stephenson books? Bored. So Amazon came up with something they once called the serendipity dial. The serendipity dial ensures that your trip across the English Channel includes the smells of the sea, the diversity of the open sky, the sound of the birds and the spray of the salt water on your face, rather than the quick, but blinkered Chunnel ride.

In an effort to move customers away from the tried and true, they developed the personalised Gold Box. What a disappointment! This was a dancing, gold treasure chest in the upper right corner of the home page that offered 10 deep discounted items per day, tailored to the individual. It was labeled, "Jim's Gold Box" in my case.

I have purchased countless books, a goodly number of CD's and DVD's, and a handful of electronics. What was in my personal Gold Box? Jewellery, kitchen gadgets, gardening tools, and electric toothbrushes. Nothing I would consider buying from Amazon.

The opportunity to protest presented itself at a Web analytics conference. "Our intent was to show you items you wouldn't consider buying from us," explained Ronny Kohavi, director of data mining and personalisation for Amazon.com. "Maybe now you will." Low hanging fruit.

How might my financial institution do the same? By taking advantage of what you already know about me. You know which credit card I use, how much my electricity bill is, how much I give to charity, how often I put money into savings and how much I've got for that rainy day. Build a data profile of me by breaking through the silos of current acounts, mortgage, savings and home insurance and then watch where I go on your Website.

If I have a dollop of dosh in a personal savings account and you see me nosing around the credit card pages, you can dash off an e-mail offering me a special rate on a new card. If I'm clicking about in the ISA area, you might introduce me to share dealing.

Keep those lines of communication comfortably open. Based on my activities on your Website, you can provide the right suggestions at the right time. If your advice has been timely in the past, I will willingly admit to my plans to purchase a car, move house, save for college or invest an inheritance.

When Amazon says, "Hello, Jim Sterne. We have recommendations for you," those recommendations are based on previous purchases, purchases made by others and my own wish list. But nothing sells books, music, toys and tools faster and at less marketing cost than e-mailing notification of availability to those who hungrily await the next Harry Potter book and will be only too happy to pay for it well in advance.

The financial institutions I do business with know more about me than my mother. If you want to get the most out of online personalisation, encourage your customers to reveal just a little bit more about themselves and you can serve them better, while reaping the profitability rewards.

You want to get the most out of online personalisation? Let your customers do the work - then you can reap the rewards.

Jim Sterne is an internationally known speaker on electronic marketing and customer interaction and the Founder and Director of Target Marketing targeting.com.

Jim will be hosting the first round table on web analytics for the Knexus community in London on 16 November 2005.