WHETHER booking theatre tickets online, or transferring millions between bank accounts, people and businesses need to be sure they can trust the internet.
Misplacing large quantities of cash would be very disconcerting, but so too would turning up at the theatre for a big night out, only to be told there is no record of your web booking and the show is now sold out.
As we commit more business and personal activity to the net we demand and expect certainty that each transaction will go according to plan - instructions received and interpreted correctly and seen only by those who are authorised.
How do we achieve such certainty? The answer of course is in the software, the complex code which provides the structure within which infinite numbers of unique transactions can take place in cyberspace.
Creating such versatile but reliable codes, is the work of a largely unseen but highly skilled group of professionals whose endeavours are progressively unleashing the full power of the world wide web.
These are the software engineers - the architects of a new world in which virtually everyone will conduct some, or even most, of their affairs via the internet.
Wales has a growing stake in this work, and in the vanguard are 500 engineers employed by BT's Computing Partners division at Enterprise House in Cardiff.
Arguably one of the most highly qualified workforces under one roof in Welsh industry, these teams, which include some internationally recognised experts, work closely with firms from many sectors to create the software that translates e-trading ambitions into reality.
They provide the essential technical expertise to different branches of the vast BT organisation - including BT Ignite, BT Retail and BT Wholesale - who in turn provide internet solutions to business.
Dr Mark Unitt, head of e-commerce at Enterprise House, explained how the software skills built up through supporting BT's own operation are now being applied across the rest of industry.
"BT has had software engineers in Cardiff for 30 years serving its own needs, but over the past five years they have focused increasingly on external customers, " he said.
A team from Cardiff worked with the group treasury and wholesale division of Halifax Bank to create a state-of-the-art system enabling corporate investors to use the web to deposit large amounts in different currencies, for different periods at different interest rates in a fast-changing international market.
It ensures absolute security, is legally verifiable and gives the user flexibility of movement down to 20-second time segments. Since going live in June 2000 it has been used to transfer many billions of pounds.
One of its vital functions guarantees that the investor is looking at the very latest information in terms of interest rates and other changing factors.
This is crucial when dealing with such vast sums, where even a slight change in interest rates can mean tens of thousand of pounds gained or lost.
"We took something inherently labour intensive, with many security issues, and created a very slick automated transactional system for very large deposits, " said Dr Unitt.
The team's experience of handling such large projects "end to end" gives them a key competitive edge, he said.
On the consumer side, the Computing Partners operation in Cardiff has supported a major retailer to deliver online shopping and, more recently, has helped Odeon Cinemas to develop a system enabling people to book tickets - and even choose their seats - online, via PCs, interactive TV or Wap mobile phones.
This gives Odeon a whole new relationship with its customers, gathering data on their film preferences and viewing patterns, and giving them information about forthcoming productions. …