I think we are all faced with this issue: we got an application from someone and we don't want to accept it. The most typical case is for employment. In my project I get many more types and very frequent applications.
I think we can do one of two things: reject it or ignore it.
I've been ignoring applications I'm not interested in but I really don't like doing that; because when I apply I hate being ignored. It's easy to do, but maybe not right. I've decided to craft some rejection letters, make the decisions as fast as possible and let the applicant now. I think that's the good thing to do.
I remember being phone screened twice by a company in London, being flown there for a whole days of interviews, and after that being totally ignored. It sucks.
In the third or fourth rejection I've got someone vilifying us on Twitter for rejecting them. These are not life-changing employment opportunities or anything like that, most people forget they applied after a couple of days and by rejecting them what I end up doing is reminding them of the application, reminding them that they didn't got in and giving them an excuse to vent.
So, what do you normally do? reject? ignore? why? any advice?
UPDATE: Just to give a little more context; we are publicly open and advertising we want people applying for this, and the applications I receive are almost like auditions, so they are not generic emails. I really feel bad about not responding.
This is mostly an opinion poll, so I'm not going to pick up an answer; but my conclusion is, I'll continue doing the right thing, letting people know unless the backslash from doing that escalates into something nasty.