Effective Advertising?

Our mailbox is constantly filled with all kinds of print advertisements. Thankfully it isn't all bills! Printing on brochures here must be really cheap because all kinds of people are fond of catalog printing for advertising. Everyone does it, even the real estate agents who freely distribute it all around. Do you think it is really effective or do you think it might just be a waste of money when people such as myself throw it out as junk mail?