Revolution Linux experimented more than 35% growth during the last year and things seems to follow the same trend this year. For us, it has been a great experience (not exempt for some growing pains !;-) and, when I look around, at open source companies, I can definitely see a trend.
Local Market (Quebec)
In our local market (Quebec province in Canada), we have more mature companies and they tend to have more people this year than the precedent (growth) and most of them seems to have find/defined a niche of some sort. Large companies are less and less generalist and have one or several specialties/focal points. We also experimented in Quebec some mergers between existing companies and this is clearly the sign of a more mature market.
Open Source at the International Level
At the international level, a continuous flow of Linux migration and open source adoption by companies, as well as a bunch of acquisition/mergers occurs as well with, once again, a more focused approach for the existing players. Some leaders start to emerge with a sound financial model and extraordinary growth and profit.
Open source = competitive solutions
More and more, open source software is used/bought, not because it is open source/free (speech/beer) but because it is a good software (intrinsic value). The fact that this software/solution is open source is not the determining factor that make customers buy it. On a head to head competition with closed source alternative, a bunch of open source players emerges (Firefox, Apache, MySQL, PostgreSQL, Tomcat, etc.) and are in a position to become market-leaders.
In practice, a few years ago, when we started Revolution Linux, we mentioned "we are doing open source, this is great". These days, we say "we have an excellent solution for you. By the way, this solution is open source and this brings you several additional advantages ...". But clearly, the customers we are reaching now are not basing their choices on the fact that this is an open source software. They select the best technology for any given task and, more often than ever, Open Source simply compete ... and win.
"It's the fast that eat the slow"
A few years ago (10), Open Source companies where almost non existing and of very limited size. Open source software where ten time less numerous and had ten time less functions/capacity/line of code than today. If "it’s not the big that eat the small…it’s the FAST that eat the slow" (see book of the same name by Jason Jennings & Laurence Haughton) is true, it means that open source development has proven that it is faster/more innovative than closed source development. And this will continue. But ... how fast ?
Inflexion point ?
My opinion is that open source is at an inflexion point : if the trend continue (i.e. : no major change from the competition, no major change in the environment, legal, financial, social domain), then the areas where open source is dominant because of its intrinsic value (i.e.: technical advantages, best solution, best product, etc.) will experiment a tremendous growth (exponential like).
Other open source solutions with smaller user base will either join the fast growing club ... or fade. Indeed, because several open source business model have a proven value, we see more and more companies joining the club and mimicking what is perceived as the root cause of the open source leader success. Some of them being coined with the not so sexy "fauxpen" term. Open or fauxpen companies fueled and increasing competition on existing solutions (including closed source one).
Open Source companies will follow the same trend : fast growing of fast waning. In the last case, acquisition/mergers will keep the talent into open source and help fuel the fast growing company.