IBM has announced plans ahead of its Lotusphere 2009 conference next week to buy online messaging and collaboration services provider Outblaze as part of a continuing strategy to develop its web-based email service offerings.

Outblaze, a Hong Kong-based privately held company, has racked up over 40 million users since its founding in 1998.

IBM plans to integrate the new purchase with its Bluehouse social networking and collaboration project, which allows users to share contacts, files and activities, and interact with chat and web meetings.

"The acquisition of Outblaze further demonstrates Lotus' commitment to delivering secure, scalable online solutions, and will help accelerate delivery of collaborative services with little to no IT involvement," said Bob Picciano, IBM Lotus Software and WebSphere Portal general manager.

Combining Outblaze and Bluehouse will give customers a choice between on-premise or online messaging solutions, IBM said, promising to give more details at next week's conference in Orlando.

The company has also announced that its Lotus Notes software is gaining ground on Microsoft's Exchange.

IBM said on Thursday that Lotus Notes licences had reached 145 million, claiming that a lot of the growth was down to industry leaders exchanging Microsoft licences for IBM ones.

According to IBM data, more than half of Fortune 100 companies now use Lotus Notes and Domino, including over 80 per cent of the largest banks.

"A number of customers that Microsoft had previously announced would migrate to Exchange are now stalling or abandoning those plans," said IBM.

"In some cases, the cost of upgrading Notes/Domino has shown to be 20 per cent or less of what companies were projecting for migration costs to Exchange. "

IBM said that new Notes customers include Coca-Cola, Nationwide, Linde Group, Global Hyatt Corporation, CEMEX, The Hartford, Banco do Brazil, Banca Intesa Sanpaolo and Petrobas.