How are players matched when creating a new town?

Solution 1:

• Non heros join a town randomly from those available.
• Heros get to choose what town to join.
• You can't (directly) join advanced towns without 100 SP.

However, when you join a city, you drag with you as many available people from your coalition as possible -- regardless of their soul score.

This gratuitous formula explains how many soul points you get by surviving for n days in a city:

See the Die2Nite guide for more, especially on the meaning of the term "surviving". There are many corner cases, like death by addiction, that discount your last day.

Solution 2:

They're filled up linearly. People who join in the same time-frame therefore come in the same town.

Once you get 100 soul points, you get to join veteran towns, which have a bigger desert and will only have other people with 100 soul points. Therefore, once you have survived for a full 14 days in the same town, you get to join a town with experienced people only.

Of course, when you're a Hero, you get to decide for yourself which town you'd like to join.

So no, they're not secretly skill-matching. They are doing it in a very obvious way.

If you're interested, the formula for soul points is where n is the amount of days you lived fully in a particular town. Basically, you add up the amount of days, which means that by day 14 you'll have 1+2+...+14 = 105 soul points.