JoeSP wrote:
...snip....

Successes?
There's been more than enough time to find something, if the original
concept were valid..

(Setting aside the immense successes related to pioneering distributed
computing) there are myriad reasons why the SETI (and SETI@home in
particular) may not succeed (I have become quite jaded myself on the
restricted nature of the search parameters), but there is no way that
anyone can calculate how much search time is enough, especially
considering the very limited target dwell times of SETI@home and the
overwhelming noise.  Perhaps their greatest weakness has been the lack
of ability to follow up on candidate signals quickly (which might be
remedied with the near real-time processing?)  IMO they underestimated
the problems with noise and rejected way too many candidates with
scoring because they couldn't follow up on anything within a reasonable
amount of time near an event.  They also seem to have gotten bogged
down with BOINK (which however will probably pay off in the long term
processing-wise).  I personally hope to live to see the day when a
scientific paper on the SETI part of SETI@home comes out! (as opposed
to other radio astronomy experments.)

Here's why they won't:
1) Radio is a very inefficient means of communication in space.
Particle-beam signals are better for point-to-point communications, but they
are difficult to intercept.

Since there are no space-based particle-beam detectors dedicated to
SETI use, the only currently testable methods of communication (and
efficient enough for us to afford receiving cost-wise) seem to be
within the electromagnetic spectrum.  I have a feeling that efficiency
has a different meaning to Type 0 civilizations (like us.)  I don't
think a particle-beam SETI paper based on actual experments is probable
in our lifetimes.

2) A civilization, were it inclined to beam a radio signal off into space,
would not know to point it at earth.

They should be able to detect Earth, and detect its terrestrial nature,
it's water, its oxygen.  There is good reason to believe that Earth's
biosignature has been broadcast in the reflected light spectra as soon
as oxygen dominated the atmosphere.  It is even (very slightly)
possible that Earth's radio sphere has passed probes belonging to other
civilizations.  There are reasons to monitor Earth.  Communicating with
us is a REALLY BIG STRETCH, but what do we have to lose by listening?
You cannot eliminate the possibility of ET electromagnetic
communications by not listening.

3) An advanced civilization, if it follows the normal rules of common sense,
would not want to advertise it's presence to more advanced civilizations.
The Incas wouldn't have invited the Spaniards into their lands in
retrospect.

There is no reason to believe that ET civilizations follow such a thing
as "the normal rules of common sense" (whatever that may be), but since
we have no idea of ETI motivations, nor they of others, it may follow
that the common sense engendered by Darwinian evolution to most wild
animals applies universally, you are either the predator, or you are
the prey (and some prey try to camoflage themselves.)  I don't share
the altruistic lovey dovey perspective of others, but I think think
it's O.K. to look for ET's who may be beyond predation.  They may have
the confidence to advertise their presence (because they can kick
anybody's ass if necessary.)

4) The age of the universe is at least 11 billion years old.

There are numerous experiments that point to the age of ~13.9
billion-ish.

We are likely
to be broadcasting radio waves for a little over a century. The odds of two
civilizations intercepting each others' radio signals is a little like two
bullets colliding over a mountain, shot at random times, every thousand
years or so.

Those odds actually sound a little optimistic :^)

5) We look for patterns in incoming radio waves.  Carrier frequencies aren't
necessary, even today. Repeating data is inefficient, and advanced
civilizations probably wouldn't use it.  In fact our own transmitted data is
more and more resembling random noise. If you listen to an intercepted
digital cellphone signal nowadays, it sounds like static.

This is an old one here.  Most people agree with what you have said.
And most people also agree that we are only looking for purposeful
directed transmissions (for dummies.)

6) As Michio Kaku often says, we are a "type zero" civilization. We have no
status.  If a type 1 or 2 civilization were to visit us, they would benefit
as much by communicating with us, as we would by talking to an ant hill.

Michio Kaku is not the first person to observe this.  However, have you
ever taken the time to observe an ant hill?  Living in Florida I have
the privelege of communicating with ants on an almost daily basis.
Today I squashed about six or seven members of a nasty species about as
long as half of your finger nail, they are really pretty smart, they
hide when you go after them, jump off the wall when threatened, and
they look for giant moving prey an sting them.  A few months ago they
communicated to me that they don't like me by stinging me; now I
communicate back to them by squashing every one that I see.  A few
months ago some of their cousins, fire ants, had the pleasure of
receiving smoke signals from me after I lit their ant hill on fire with
gasoline (that was some primative fun!! Die you fire ant bastards
die!!!)  Yet another species, carpenter ants, gets my chemical messages
that I leave around the perimeter of my house, and they never come in
any more.  So you see, it is possible to communicate with the ants, you
just aren't trying hard enough :^)  Maybe ET should do the same!!!
  

Jason H.