I have MS office software and open office, and I hardly ever use either one of them.

And, oo sucks at using a excel spreadsheet with graphs. The few times I've used it when working at home were painfull.

72% of the users has Microsoft Office and 17.1 has no productivity suite installed. It means that 10.9% of the users has alternative software as its only solution. That is good.

100-17.1-2.7-1.4-0.3-72=6.5% is the minimal unique OOO users.
These 6.5% have only OOO installed.
Considering the fact that some uses more than one, my guess is that "active users" are somewhere at ~15%.

As it was pointed before, there is no problem to have more than one office suit installed. Each instance counted. it means that at least 100-17.1-72=10.9% of users have both MS and OO office suites installed.
Simple math.
As for compatibility. Each MS Office version has compatibility issues with others. IMHO (created by experience), OOO is more compatible than MS.
Features ... Everything I ever needed, was done. So there are "useless" features in MS office. I guess MS Office misses some of the OOO.
It has better guessing what toolbars should be displayed and what the content of context menus should be depending on object in focus (tables, pictures etc.)

As someone already pointed out, it is installed but hardly used. They should isolate those who have ONLY OO. The rest would certainly be using mostly the M$ solution and the OO was there only to see how it looks like.

If this 20% of OO is inside the 80% of M$ then I'd say that these results are pretty sad.

OF COURSE IT ADDS UP TO MORE THAN 100% DAMNIT.

The better question is: what office suite is being used? Just having a freeware office program installed doesn't mean it's being used. Besides, as others have pointed out, the total percentage exceeds 100.

I use OO for years and years and never had any problems at all.
And I don't want the 300+GB M$ Office installed just so I can see a paperclip running around on a bike.
OO is a clean office machine...and FREE! LOL :-)

I think OpenOffice.org is a good product. Just needs to run faster and support .docx files. As for the UI, it's good enough but pales in comparison with what MS is offering now. Then again, it's free and it works.

I have used it a time or two in the past without any issues besides formatting when opening MS Office documents. I do, however, have two friends that do some very serious spreadsheet work and they both tell me that the OO spreadsheet is pants. (Crap if your from the US like me)

More like logical, also Star Office was originally a German product. Hope the take up is as high elsewhere, (or higher).

@NoOneYoudKnow
That's because some people can have more than one suite installed.

@Jammed
You are either spreading BS or you didn't read carefully. If you care to check out the links you will find out that they used Java Script to determine the installed fonts, so it's your browser that is the spyware, not Open Office. If you are paranoid, use the NoScript extension for FireFox, but get your facts straight.

It seems to me that the numbers are inflated by bundling the Open Office Suite with the Java Run-time installer. I think that most of the installed Open Office suites come from there.

Add the numbers and you get over 100%

I really do, MS Office is not following my needs for a while now (I really dont care about the whole server slash sharepoint corporate BS that is now "office ecosystem"). However, with the present UI the OpenOffice 3.1 is simply unusable as a serious productivity tool. They (OO) promise that version 4 will have a complete UI overhaul, if that is so it might be a dropto spill the glass for MS.