Besides, if you’re an AI or an uploaded brain, you can send yourself over a communications link. That’s pretty valuable, regardless of whether you ever intend to return!

The news in my town is of interest to me, nobody else would care about the latest live music at the local stage.

Science might be of interest, but the problem is both cultures will work in parallel, so we can assume that majority of advances one planet discovers are discovered by the other planet in the mean time.

The nearest star (which might not even have a habitable planet) to earth is too far away for science collaboration other than the "here is new type of signal we are sending your way, see if you get it", and even then you take the risk that the other planet chooses to not listen for whatever reason (it wouldn't surprise me if some theory require this level of cooperation). It is close enough that some "we are studying this lead, so you probably want to look at something different to avoid duplicate work".

As we get farther and farther from the other planet collaboration is less and less useful. You quickly reach a point where the planets can advance faster by duplicating effort than talking to each other (other than as a much latter verification of current theories)

Of course if we colonize a planet 100 light years away you can assume a few hundred years of the colonists working hard to establish the colony and so getting science and technology feeds from Earth will be useful since then they can make a copy of widgets without having to design it from scratch. Eventually they will get established and start producing their own science locally, and soon the feed will be useless and not of interest.

After going back to India, merely showing things to people on Google Maps was an experience of its own.

People went like: Do people in other countries, live that well?

I'd fathom when we see some advanced civilization we would probably react the same way.

Also keep in mind than until recently on earth we used transmission mechanisms for long-on-earth distances that were closer to the order of magnitude of 100-year transmission time (a few months) than to present transmission time (a few milliseconds).

I don't know if it is possible for a civilization to connect the past to the present over such long periods of time. The individuals in each generation would have to pick up, use and pass on all the information that came before.

Our capacity to take past information into account, individually and collectively, is very limited, even if it gets stored somewhere. We can see that in many debates on here where arguments of the past are repeated many times over without younger participants having any awareness of what's been said before.

We can compensate for that to some degree by continuously retelling old stories. But relearning old stuff necessarily competes with new information for our limited mental capacity and so old information inevitable degrades over time.

Even religions, where there is a strong emotional incentive to retell old stories, are struggling mightily with even understanding what the original authors meant by the words they used and how to apply any of it to the current situation.

I think for a civilization to retain its collective memory over much longer periods of time requires completely different individuals. It requires individuals that are able to grow their mental capacity at the same pace as the amount of accumulated information grows.

If you consider the combinatoric explosion, this is unimaginable in a biological organism based on evolution and ultimately even in an AI.

Definitely in civilization time that leaves a lot of room for a few milion years here and there, but still, we could be the oldest and most advanced (at the same time I do hope there is a civilization out there less eccentric and egocentric as ours...)

If it's communication, that implies a two-way exchange of ideas. The galactic equivalent of blogging would be like all such communications: typically of more interest to the sender than the receiver.

If we assume a long-lived species that can receive a response within its lifetime, we must also assume that during the intervening time little enough of the context has changed that the answer is still relevant. That means a species and a civilisation that has extremely little change over hundreds of years.

This is what I mean by an extraordinarily static civilisation.

(But if it's so static, what could possibly be said that has material bearing on anything? :-)