IBM HAS advised 20,000 of its technical staff to drop Microsoft Office in favour of productivity software from its Lotus subsidiary which adheres to open standards.
A memo from IBM's chief information officer Mark Hennessy and vice-president Gina Poole was sent to staff yesterday.
Although the memo, seen by The Irish Times, does not explicitly mention Office, it talks about "a new, more integrated approach to desktop productivity software" that is facilitated by using Lotus Symphony.
IBM and Microsoft have been at loggerheads over the format in which Office saves documents.
Last year, Microsoft tried to fast-track its Open XML format for standardisation by the International Organisation for Standardisation (ISO), but IBM lobbied hard against it.
A competing standard, Open Document Format (ODF), achieves the same task of separating the information from the software creating it and is backed by IBM, Google and others.
Last week, ISO said the process had been stalled following objections from Brazil, India, South Africa and Venezuela.
With more than 90 per cent market share, Microsoft would suffer little financial impact even if all 20,000 IBM workers switch to Symphony. But it sends a clear signal to the software giant on which way the wind is blowing.
Despite being one of the world's largest technology companies with more than 380,000 staff, IBM has become adept at adapting to new trends in recent years and is a strong supporter of open software standards. In 2000 it began to make a major investment in the Linux operating system when it was still considered marginal. It is now used on everything from supercomputers to mobile phones.
More recently it has encouraged staff to write blogs, use collaborative "wiki" tools and get involved in social networks.
The memo notes that Symphony's use of ODF "makes digital information independent from the program in which it was created" which means documents can be accessed from any platform "allowing information to be used in new, innovative ways".
The news comes in a week where EU Competition Commissioner Neelie Kroes said the EU should vigorously pursue a policy of buying open source software.
"For all future information technology developments and procurement procedures, the commission shall promote the use of products that support open, well-documented standards," Ms Kroes said. "Interoperability is a critical issue for the commission, and usage of well-established open standards is a key factor to achieve and endorse it."
Microsoft has worked hard to prevent governments dropping its proprietary software in favour of open source products.