Does the Sol system have a slingshot?
Also, in the back of my mind is the thought that the Sol system does not have a slingshot. So to trade with Earth, you need to first travel a short distance to another system.
The implications are huge:
- The Earth could be very isolationist, much like America in the first half of the 21st Century.
- I want a sense of remoteness to build up the development of colonialism and gunboat diplomacy.
- There could be three trade factions
- Corporate - upspin
- Clan - downspin
- Government - Earth to nearest slingshot
The real impact is that communication would be on the order of years and not months.
When man first starts exploring other stars, it will take decades to get started. A good story would be the impact of the discovery of slingshots on colonial governments. Where mandates used to be ignored because they were very out of date, they suddenly start becoming very pertinent. If ignored, your replacement might arrive in a few months.
This would force expansion to further sites along the slingshots. Each slingshot would take a rebellious sole further away from Earth. Get far enough away and you might be back in the years. Of course, what happens when you think you are far enough away and the next link takes you back in a loop to the Earth link? :->
Or it might force you to go further down systems which are not connected via the slingshots.
I.e., the first expansion would be out towards nearby systems. The slingshots would not follow those paths. So we would see the development of newer stations with closer ties to the Earth. These would be the corporate traders.
And the earlier expansion could see the rise of the trader clans.

