Of the almost 500 questions, well over 100 questions are unanswered - that seems like a worrying statistic - is it of concern?
In some ways yes, it is a cause for concern. In other ways it's actually a healthy sign.
The main issue is that the topical range of this site is huge — covering many disparate professions. Having a software expert on hand for every category of question is simply not going to happen until we are a lot bigger. In the mean time some questions might wait quite a while for good answers.
It is, however, a good thing that a lot of questions are getting clarified, voted up, then left without answers. The alternative that we make a push to put up a bunch of half baked answers that are rehashes of Google results by people who have never used the software related to the field would be a dis-service to our aim. Those very unanswered questions are exactly what might eventually attract a domain expert that knows the answer! If all the questions get mediocre answers, they are less likely to be dug up again.
A further issue is that a lot of questions are going to want something that doesn't (yet) exist. People want software that does exactly what they want the way they want to do it, and that isn't always going to happen. A fair number of questions may simply not have answers because there are none to be given. This goes with the territory I think.