How will the crazies respond? Will new cults start? Will this mean the end of organised religion on earth? Or will it just mean a fresh batch of religious wars?

Obviously Pat Robinson will raise funds on TV in order to built a space vessel to transport missionaries there to spread Christianity to the martians. And probably something about Sally Struthers and Ethiopians too.

On a more serious note, I believe the most meaningful impact would be possibly answering the big questions about the origin of life. It is hard to make generalizations of what 'life' is when you only have one type (DNA based) to study. Also, finding truly alien life somewhere so close could say something about the abundance of life in the entire universe - right now it's complete guesswork.

Is there life on Mars? It's certainly possible. I think that beyond that we are just speculating. I personally think we'll find microbes, or something like that. How much that matters scientifically is anyone's guess, and depends more on what we find. If we find life forms not based on DNA, then that's quite the scientific discovery, as an example. Life on Mars will mean that life is possible on other planets and that therefore even complex life can certainly exist on other planets.

I'm more curious if Fermi's paradox may finally gain some more credible answers from the discovery of life on Mars (if it exists) rather than the usual guestimated theories...

Could such an organism be useful to us in some way? How could we exploit it?

...

How will the crazies respond?

;)

If there ever was life then there will be life now. Life will evolve for any climate where there is even the smallest chance of survival. The question is whether the prob can detect it or not.

I'm also a person who doesn't really get why discovering primitive life (by primitive I mean 1 cell stuff, only that we can expect on Mars) is so interesting.

The only way I think it would be interesting, if it were totally different from what we expect. Like not carbon based, not anything like DNA based. Let's hope that the probe would be able to detect these other lifeforms.
Otherwise I only see it interesting from some philosophical viewpoint.

Discovering non-primitive lifeforms would be interesting, because that would mean grow the chance of finding "intelligent" lifeforms, which would be fraking interesting. There are some (or many) theories that say that there has to be some quite fine tuned cyclic dramatic extinction events to keep evolution running and keeping life from "sticking" in some primitive but well working system. This cycle has to be tuned so that many ecosystem variations can evolve and vanish, but a system can evolve to some degree without extinction again. If this is true, that would dramatically decrease the number of places where advanced life can evolve (Obviously, by fine tuned I don't mean tuned by someone, but by some accidentally evolution-friendly natural cycle)

Okay, maybe these theories are disproved anyway, I don't know where evolution theories stand today.

Mars is a prime example of the remnants of a civilised and technically advanced culture which unfortunately had their online-activation servers mistakenly go offline for a week.

Remember folks, just say no to naive DRM methods..

</troll>

Are we even ready to find life on another planet? We barely show enough goodwill to each other. Because right now, we're nowhere near the Star Trek level of social, philosophical, and political sophisticaltry (sp?)

Yeah too right.. And all our handheld scanny things are all locked down and/or crippled in some way. We could never resemble Star Trek without those!

It would be very hard to download the "Alien Zog Scanning App" from the AppStore when we are lightyears from home without of course a special jail broken version where we could simply write our own on the fly... Otherwise you would need a mac... and a special developer activated iphone.

Not even Scotty could get round that!

I'm also a person who doesn't really get why discovering primitive life (by primitive I mean 1 cell stuff, only that we can expect on Mars) is so interesting.

Because right now all we have is one example of life, here on this planet, which it seems makes this planet unique and special. Finding life somewhere like Mars (either existing or dead) removes that specialness and proves that life could very well exist else where.

Maths and some science (such as organic compounds found on meteorites) seems to indicate that life is pretty much evitable; we just can't seem to find any on another planet right now.

Mars is a target because its the closest viable target for 'dead life', beyond that we have to look to Europa and Titan as potential life sources but those are currently out of our reach - by shooting for Mars we get to develop new tech which will also help the hunt for life on those bodies too.

What is it about spaceflight that attracts the "But there are better things to spend the money on!" arguments?

I mean, we might as well pick on the billions being spent on the upcoming Olympics. Or money spent on wars. Or, the who-knows-how-much-money spent on advancing computer technology just so that people can play games or post to Facebook. The thing is that what is important to you isn't necessarily what's important to other people - and unless you're spending all your money on saving the rainforest or helping the poor, you're in no place to criticise how other people want money spent.

(How would money have helped avoid the financial crisis anyway, out of interest?)

When you buy a new car, it's well regulated how much CO2-per-100km is allowable and whatnot, and you're told to save energy, you can't buy real lightbulbs in the EU any more, and everywhere you're told about "green" and "eco" and all that bullshit (much of what's "eco" is just as bad or sometimes worse anyway, getting to think of this poster I saw last week about using the gulf stream to produce energy) -- a single unnecessary Atlas V launch probably produces as much CO2 as a million people are able to economize in a year.

Well I'd like to see a reliable source for the "probably". And the examples you give aren't about stopping people from driving cars or having lights, but about making it more efficient. Do you have a more environmentally friendly way to put a space probe into orbit, or to another planet?