Let's talk aliens

Possible spoilers ahead? I'm not sure whether this is really obvious to everyone and just no-one mentioned it, whether I'm just plain wrong or whether or not it's a plot point, but if you want to play it safe, I suggest not reading on.

Spoiler:

As long as we're talking radio, it's an easy one. Nobody would use a single-freq high-amp omnidirectional radio signal for interstellar communications. It's just an error-prone waste of energy and frequency ranges. Even a stupid Wi-Fi chip knows better.

I strongly doubt anyone would use EM waves at all. They are too slow compared to the distances Out There. Moon is half a light second away, and it's already a bother. The second nearest star is about 3 light years away. No conversation would survive a six year delay between a question and an answer.

Now, you'd probably think that scientific data might still be relevant after all these years. Highly unlikely. Right now, a primitive civilization of half-intelligent apes still clinging to their only planet boasts doubling its knowledge once in 12 months. By the time they evolve into, or create, a truly intelligent breed able to get the hell off this rock, it would probably be happening within milliseconds. Granted, some questions would still stay unanswered for much longer, but chances are they would still be answered long before a material body reaches some really far away point in spacetime and its signal comes back home.

Finally, if there is a possibility of faster than light communication, that's what everybody's going to use instead.

And, of course, letting Everybody Out There know your exact position is hardly a good idea, and nobody's going to sit on planets orbiting stars for any longer than they absolutely have to. Competitors annoy, often with consequences. Planets suck. We're looking for the wrong things in the wrong places.

Now we're going into my own personal opinions on the Fermi Paradox, but I think you may well be thinking too small. If we assume a "large" number of independent civilisations have at some point arisen in our galaxy (we'll stick to galaxy for now), then the question becomes: why hasn't the galaxy obviously been strip-mined for some form of resource by von Neumann machines yet?
Here I'm imagining specifically machines which can be sent off to a solar system, collect accessible resources, replicate themselves a few times using collected resources, send some copies off to new solar systems and send a proportion of resources collected back to the home system.
Given that we haven't yet invented any von Neumann machines, it's a bit tricky to know the required investment in start-up materials. But if we assume 100 years' travel to the nearest solar system, combined with some mass-drivery way to get resources back home at even relatively low speeds, you could be looking at incredibly high returns on investment within a couple of centuries. Assuming that within a few centuries we still have a capitalist, non-post-scarcity society in a few centuries (a big if, I know) and there have been no advances allowing proper interstellar colonisation (in which case the Fermi paradox recurs in its normal form), then I would honestly expect us to do this.
And given that under these assumptions it doesn't seem unlikely (to me, anyway) that we will do this, given a reasonably large number of civilisations I would think it would be almost certain. That is of course if there isn't some organisation of species which has decided strip-mining everything might just be a bad idea, which is I would say one of the most likely scenarios which wouldn't lead to this.
And once there are self-replicating machines spreading across the galaxy and sending anything valuable home, I'd expect us to see some evidence.

Obviously I'm making a hell of a lot of assumptions here, so anyone is of course quite entitled to disagree with me, but still.

Uh, but what's "valuable" to folks who can send their mining machinery to other stars and get the stuff back? I'll be damned if any human knows for sure. Maybe we already see a Galaxy lacking something that should be there. Maybe we'll need it too when the time comes. Maybe not. We've seen life on this planet evolve to make do without resources destroyed by previous generations, or adapt to poisons produced by other organisms to the point of urgently needing them, be it oxygen or caffeine. We've seen human cultures switch from bronze to steel when easy to obtain tin was consumed, from blubber to kerosene when whales became a rarity. Surely, the same must be happening on a larger scale, too. If something's lacking, an obvious solution is to switch to a technology that needs other materials that are plenty at the moment. Which may lead to a Galaxy evenly strip-mined of everything in turns, so there is no single obvious lack for us to notice at all.

As for colonisation... I don't think it makes sense. If you have a space transportation technology good enough to get you to a planet hundreds light years away, you have a space transportation technology good enough to stay away from both stars and planets forever. Why bother terraforming a piece of rock orbiting an uncontrolled thermonuclear explosion if you already have a highly autonomous artificial biosphere to thrive in?

Fair. But while I'm always happy to talk about the Fermi Paradox, I still have absolutely no idea what anyone thinks of the relevant part of my post.

[EDIT:
And because I apparently cannot let anything lie, I think that the fundamental difference of opinion is that we're thinking on different scales. My reasoning has mostly been along the lines of "It seems likely that this thing has a let's say low-double-digit percentage chance of happening in such a way that it would be really obvious to us. Therefore, since it apparently hasn't happened in that obvious way, we've moved from no other intelligent species to no more than probably around 20 other species before this state of affairs becomes vanishingly unlikely, so we've not really made any progress."]

The possibilities are too many. What do we know about time? Pretty much nothing, except for the obvious fact that time travel ability is highly independent from spelling skills. Then again, all you need to move in time is a special talent easily unlocked by a few exercises. Chances are that it's not a trait specific to humans, and time travellers would appear among any time conscious species long before they are able to build their interstellar machinery.

As you might have noticed, right now I'm thinking about the scenario where a race, having mastered time tricks, creates its own separate spacetime, one perfectly suited for its specific needs, and thus completely removes itself from its original universe.

Which, in turn, may well make humans just a bunch of pests in somebody's paradise garden, and Gaia a pest control team. We don't see anyone tinkering with our universe because it was built to somebody's specifications from ground up.

On a second thought, time travelling ability, especially until trained and tamed, may actually disrupt spelling skills. At least in part, spelling is about pressing the right button at the right time, isn't it? If you involuntarily wobble on your timeline a little, you may easily get the very sort of typos our friend Luke Timewalker is famous for.

Definite spoilers. What follows is from one of the pages behind an authcode gate:

Spoiler:

Authcode gate aside, you're collectively onto some interesting, and relevant, ideas. And I snerked hard at "Luke Timewalker".