[pjc50]

This is small-p politics.

In a hierarchical organization, you can give directions to your direct reports. You cannot give directions sideways. You certainly cannot give directions upwards, unless it's for something legally binding like safety.

This means you need to ask nicely, to persuade, invite, and probably compromise. It's a very different set of skills.

(a "non hierarchical" organization has a hierarchy too, but it's more fluid and hard to see)

[lmm]

Nah. All organisations have relationships, and the ones that appear on the org chart are usually a small subset of them. Actual hierarchies are extremely rare, e.g. even in an officially very hierarchical company there will usually be loops because someone nominally low actually controls someone nominally high.

[pas]

Also, for anyone who's new to this, hierarchical organizations have an informal/shadow hierarchy too, usually an extension of the de jure one.