Marketshare information specificly for The Netherlands is very scarce. The Dutch ICT magazine Computable Automatiseringgids regularly publishes statistics / market researchinformation by MarketCap. The actual artcle is only in Dutch, but I gladly took the time to translate the highlights.
First the chart, which says it all basicly :
This research is undertaken by MarketCap in preparation for a new report on th use of Open Source Software and Linux. The initial results of this research show a big difference in markshares for Groupware in the market for Linux users compared to non Linux users.
This research shows the overall marketshare for Microsoft Exchange at 65,1% which is by far the largest compared to Lotus Notes (16,2%) and Novell GroupWise (18,6).
The research is done in the business market in 600 companies of 50+ FTE.
Source : Computable Automatiseringgids, Friday June 3, 2005