I don't know if this behavior is normal but I would expect a bit more from hirers advertising on HN. Especially when they ask for very specific things that I know I got on my CV.
I've been unemployed for nine months, though I've only been seriously applying for jobs in the past three. (I consider the first six months a well-deserved vacation. Employers apparently consider it the mark of the unemployable. C'est la vie.) I've received exactly zero (0) replies to job applications that weren't automated "we got your application" e-mails. Even at a company where my CV was handed directly to a manager by a friend who worked there, the manager stopped communicating with me after his initial "we'd like to set up a time to talk to you" e-mail.
I completely understand that employers get bombarded with applications for every single position they post. (When our department posted a [low paying] Linux sysadmin position, we received over 100 applications, of which maybe 25 had anything to indicate that the applicant had ever used a computer, let alone Linux.) But a simple "thanks but we're not interested" e-mail would certainly be nice when you've been eliminated as a candidate for a job...or were never actually a candidate to begin with.
The silence of the job search quickly becomes deafening.
It can be disheartening, because when I'm looking for work, I also spend a lot of time on applications and generally only apply to one or two companies at a time so I can devote attention to the interviews et al. Also I'm not usually looking for any job so trying to hit as many companies with my CV as possible is not my modus operandi, but it feels like that would be more appropriate, or at least get a better rate of return on effort applied to the process. :/