The courier puch is just a fancy bag. It goes in a bag slot and can hold anything.
As for the Shared Effort, etc. These are the levers in the city. Most city levers need to hit 40 and then it will set off some sort of buff. Many levers cancel out other ones. So while you work on one specific type of conversation, you will see that lever rise and the other ones fall (hence the negative number). Basically, if you reach 40 on one one of them, you will set off a buff for that city.
If you want the spoiler, here is a list of what each lever is. For example, if you parley with soldiers and use the convince conversations only, once the lever reaches 40 everyone eill get a +5% accuracy buff.
After a lever reaches 40, it will slowly fall back down. You can usually max them out at 70 and it will fall more slowly. Unless of course another diplomat is pushing up a different lever and knocks yours down.
It can be hard to get levers up when a lot of diplomats are leveling in the area as they tend to push down the levers.
Also....the more presence you have with each class, the easier it is to push up a lever. Once you become "known", the levers move 2 places. Once you are "respected" they move 4, etc.