I would like to know which are the leading Web Content Management
Systems according to their Market Share.
Background: e.g. the TOP 10 worldwide and which revenues/market share
they have. If data for "worldwide" is not applicable, a "US economy"
survey would be nice as well.

imnet,

There is an extensive report on content management systems available
from Wintergreen Research:
http://wintergreenresearch.com/reports/ContentManagement2002-2007.htm

Unfortunately, the report costs $2,800. So I will keep looking for
public information.

imnet,

I'm sorry to say that I have yet to find a satisfactory answer to your
question. While I keep looking, here are a couple of resources I have
found that may be of use to you:

First, an online copy of the Gartner report "The 2002 Integrated
Document Management Magic Quadrant" that evaluates the Content
Management industry players based on "Ability to Execute" and
"Completeness of Vision"

http://www.mis.ed.ac.uk/about/misc/UCISA/Gartner%20Magic%20Quadrant%20EDM.pdf

Another Gartner article entitled "Will Microsoft Own Web Content
Management in 2005?" claims there is an 80% chance that Microsoft will
dominate the market by the end of 2005:

http://216.239.33.100/search?q=cache:-vONfinVZ7QC:www.clunet.edu/ISS/lib/gartner/research/105400/105403/105403.html+%22Will+Microsoft+Own+Web+Content+Management+in+2005%3F+%22&hl=en&ie=UTF-8

I will keep looking, and will post an answer if I can find the exact
data you are looking for.

imnet,

Just to let you know, I have seen the Wintergreen Research report I
mentioned above, but unfortunately it does not have the information
you are looking for.