This page shows the popularity of programer's text editors and IDEs. The following lists them in order of search results by Google Trends as of 2007-08.
This is not be a very accurate measurement of user base, but can be used as a starting point of understanding.
Those in parenthesis are text editors not used for programing, but included here just to give a context, and can give some sense about the accuracy of Google Trend for market share.
Ideally, i'd like to list all programer's text editors and IDEs, by the number of users. (and limiting the entries to 10 or so) Preferably, also show the data by a pie-chart so that we can see the relative gap between adjacent entries. (for example, when shown as a pie chart, Microsoft Word and Visual Studio together might be 90%, while all the rest is just 10%)
I haven't done much research on what IDEs are common on the Windows platform. (Never developed for MS technologies) So if you work in the Windows platform and knew some of the commonly used IDEs or editors, please let me know.
Among the above list, some editor should be there but for one reason or another i wasn't able to use Google Trends to get some sensible statistics are: Microsoft Notepad, Programmer's Notepad, Borland Delphi, Kate (text editor), GEdit, roughly same popularity as Nedit according to google trends, but it doesn't have Wikipedia entry!
Also note: Google trends has records back to about 2004. This conveniently marks the beginning year to be considered on this list. Personally, i've been using Mac in about 1991. Many IDEs on the mac has come and gone. From roughly 1990 to 2002, the following are the major editor/platform used on the Mac, each basically replaced the previous one chronologically: Macintosh Programmer's Workshop, THINK C, CodeWarrior, SimpleText. But since the arrival of OS X, CodeWarrior and SimpleText went extinct primarily due to the platform change and arrival of XCode and TextEdit. Also, BBEdit is widely popular throughout the 1990s, but its user base gradually declined with the arrival of OS X in 2001.
We all have heard “vi vs emacs” a million times, and have participated in brawls and polls about which editors are the best. Although, these are almost always carried out in a facetious fashion among tech geekers, without any hint about the social importance of these kind of questions.
Statistics such as market share, is broadly speaking part of the info and activity of demographics and market research. Such information is very important in decision making, and corporations will often spend tens of thousand dollars to research or buy the info. (there is a entire sector of businesses dedicated to market research) For example, a corporation will need to know its market share to make decisions on marketing budget, development budget, pricing decision, corporate buyout negotiation, down to the technical details of a feature design. Good and bad directional decisions can mean success and extinction. (For more on this, see Wikipedia Market research. )
Non-commercial software such as emacs, isn't dependent on paying customers nor driven by financial investors, so, many market questions does not apply. (In a sense, nobody really could care if a particular open source software went extinct for lack of users, and thousands big and small come and went all the time without a blip on radar.) However, getting users and getting info about users is still a important aspect in understanding and for improving our software, because we like emacs and want our time investment into it survive. We, emacs users, care, and care a lot, on emacs's popularity or survival. (put it in another way, we don't want to have to be forced to switch to vi due to emacs dilapidation and oblivion.)
As a example of importance of the info about market share of editors, consider emacs advocates and Free Software Foundation (emacs developers), in their consideration of modernization of Emacs. If emacs is used by majority of professional programers (defined as those who makes a living primarily by coding), then perhaps it is not so important to changes emacs to conform to modern UI. But if data indicates that, emacs is today less than 1% of the programing population, then the modernization of emacs issue warrants much more weight.