So often it happens that one has read and carefully followed all the instructions associated with a job application and are in fact quite confident that one is a great fit for the job but months go by and there is no response. In other cases, you are told that your resume and profile is in the database and the recruiter will get back to you as soon as they find a job that matches your profile this is again followed by radio silence. Generic rejection letters are not going to tell you the actual reason you were found unsuitable and when you do not have a clear explanation about why a job offer was not forthcoming it is difficult to stay motivated to keep trying.
Here are some reasons that a job passes you by without any wrongdoing on your or anyone else part. With the glut of people job hunting today, applying for a job on a company website is quite often akin to throwing your resume into a black hole. There are so many resumes that pass through this channel for such few jobs that each gets a very cursory look from a over worked recruiter looking for a reason to reject the resume. The wrong zip code, or a weird online presence may disqualify you. The recruiter will only remember a person that stands out in a positive manner for some reason and not all of us do so.
There are some jobs that are posted online as open to all for legal reasons, but in actual fact have already been filled by someone within the company. These are jobs for which you may keep applying and make no headway. Other times you may work for a company with whom your prospective employer may have an unofficial no poaching code which will result in your application being rejected.
In such as situation it would be good to know the odds for selection. How many people the company hires out of all the people that apply, this is information that companies do compute, but do not share.
In a perfect world each prospective employee would get a fair hearing, but that does not happen and the best that you can do is to stay positive, try to work out ways to stay in a recruiters sight without being irritating, make your contacts work for you and hope you land that dream job someday.