I applied online for a job last week at 2am (problem sleeping) and I got a standard email at 8am to say - thanks but no thanks.
The position had been open for 2 weeks before I applied.
Don't get me wrong, I don't think I'm amazing and would get hired on the spot BUT I do get the impression that maybe in the first week of it being advertised they must get so many applicants that if they already have a lot that stand out then they won't even look at your application.