Looking at Web Applications questions, I've noticed that many questions are in Community Wiki or should be converted with CW flag (this one for example).
Is this because the typical question on Web Applications is "recommend me a...", "best site to..", "x versus y"?
From what I see, Community Wiki flag in this kind of Stack Exchange site does not fit very well.
Most questions currently are of the type "Recommend me an app for this", "Alternatives for X" and so on as you said.
I think it has a lot to do with the way the question is asked: looking for a web app to solve a problem should not result in a community wiki (I verified on superuser and they don't transform those kind of questions in community wikis). However, if the question is of the type "list of web apps that do this", or something like that, then the question is not asked to get a definite answer and should be made a community wiki.
I think this problem might be because of webapps is relatively new.
Whenever we see a question that doesn't quite fit the mold for a "real" question, I suggest a rephrasing of the question first instead of automatically asking to flag it as a community wiki.
I remember a few days ago that Jeff was talking about this very issue in the chat and said something like the reason there are so many webapp recommendations is because webapps are usually free and instantaneous to access. He was giving the example of a travel site and said that if traveling was instantaneous and free, you would get a bunch of questions about places to visit.
