I can't stress enough how important communication is on both sides of recruitment. We've all been on a job-hunt, itching to hear back whether we have the job but this doesn't mean you need to pester a recruiter to find out the status of your application twice a day with every communication channel possible.
It goes without saying that a candidate who proceeds to an interview/assessment stage should receive some form of notice. The candidate knows that, and so does the recruiter.
Don't get us wrong, the enthusiasm is great to see, it shows that the candidate has a true interest in that role. Just have a little faith for at least the next three days. If after this you haven't heard back (in the case that they didn't tell you a date they'd get back in touch), then give them a direct call. Leave them a voice mail if they don't pick up. Still no communication after two days? Drop them an email but at this point, just leave it be.
HR people can’t reply to everyone who applies for a position, but everyone who’s called in for a first interview and doesn’t advance any further should receive some form of notification.