Re: Beams don't need to be aimed at us.
No, the photon density is too low for non-targeted beams (which probably don't exist) unless you refer to the much much lower probability of us accidently being in the path of a tight beam.
It's not difficult for an advanced civ to send targeted beams to all solar type stars in its glactic segment.
And as many have said, if advanced civs have no interest in contacting newbies with old fashioned EM waves there are no signals and if they are using tachyon beams or some other sci-fi method, no signals.