Retailer John Lewis is integrating its in-store and web order systems to create a single view of customers to help it cross-sell products.
The project, which involves developing software to integrate in-store and web order systems as well as Epos terminals, will be complete in 2011.
Robin Terrell, managing director at John Lewis Direct, said that as online sales increase the role of stores will change. "Customers will experience products in-store but buy online," he said.
Retailers have multiple channels to market - online, catalogue and stores - but record customer information separately.
Like banks retailers realise they are missing cross selling opportunities by not having a clear view of how customers buy making it difficult to analyse trends.
Achieving a single view of customers requires major changes to the technology infrastructure, said Terrell. "There is a lot of heavy lifting required. This is the largest technology project we have ever embarked on."
He said the software development will be completed in-house.
The retailer began its online sales strategy in 2000 when it acquired Buy.com. The site took until 2005 to become a profitable business for John Lewis, when it accounted for £115m of its total sales.
In 2008, John Lewis made £327m worth of online sales, overtaking sales at the company's flagship branch in London's Oxford Street. Online sales accounted for 13% of total sales last year and increased by 22% compared with 2007.
Peter Fitzgerald, head of retail at Google UK, said a single view of customers is vital for retailers to understand how people spend their money.
He said the analysis of customer data will help retailers target and service customers, which will in turn increase sales. US retailers are ahead of their UK equivalents in terms of building single views of customers, he said
Over 50% of John Lewis' total sales begin online, but only 13% of total sales are made online because customers go online to get ideas, said Terrell