It might be a salesman, a survey or ... a request to come for a interview.

Before this exciting event you have sent several applications to numerous companies. Probably you don't get the company name right away and you don't want to sound like a dumb so you don't ask it several times. Anyways, you do agree that you have applied this position and you are ready to arrive for an interview. Then you agree with details and time...

I have to say very few things beat this feeling. At least those things are not allowed in public places.