There was a position-opening announcement posted in a department's homepage of a research-focused institution in the US on February 14, 2015. I firmly believe my experiences and track record make me an excellent fit for this opening. Therefore, I applied for this position on-time. It was mentioned in the opening description that application material must be received by April 14, 2015 to receive guaranteed consideration, though the search will remain open until the position is filled. However, the strange thing which I noticed that the same opening was posted again in their homepage with new a submission deadline (i.e. June 14, 2015). I then reapplied for this opening. Two months later from this new date, I contacted the Chair of the search committee and asked the status of my application. However, I did not get any response from him. Just today I got notified from job search engine (verified also in their homepage) that the same opening has provided a new application-submission deadline which has been set to November 1, 2015. I am curious to know what this means. Does it mean that they have not found any suitable candidate for this opening or something else?
I don't know what kind of position it is, but are you sure it's not additional instances of the position being offered?
That said, it sounds as if they're not getting the applicant pool or number of applicants that they want. In my experience, hiring committees want three or four good candidates, even if one stands out from the rest.
Maybe they have found that your qualifications don't meet the requirements as well as you think they do? Your not getting an email back from the search committee chair is probably significant -- or maybe your email got lost in the internets.