How can I have rooms with identical short descriptions? Like, I have a room “The Street is a room.” - how can I have another room to the north which also has the short description “The Street”?
You want the “printed name” property. Give them distinct internal names and then set the printed name to whatever. You can use printed name for other cases where it’s difficult to refer to things in your source with similar names.
[code]Street1 is a room. “This is a street.” The printed name is “The Street”.
Street2 is north of Street1. “This is another street.” The printed name is “The Street”.[/code]
EDIT: And let me expand on this a bit to tell how I found this out. I went to the Index tab and the Kinds tab under that. Near the top, next to the room kind, I clicked on the little magnifying glass. I see the room kind and I look under “Can have”, but there’s nothing there that looks promising. So then I scroll up and look at room’s parent, object. Under object’s “Can have” is “printed name (text)”, and this looks promising, so I try setting the printed name property.
-Kevin
Thaaanks!! 
For bonus points (or rather, if you wanted many such rooms), you could use a kind:
A Streetroom is a kind of room. The printed name of a Streetroom is usually "The Street". Northstreet and Southstreet are Streetrooms. Northstreet is north of Southstreet.Check out the “Tiny Garden” example (#62) for a way to have many similar rooms that are distinguishable using auto-generated descriptions.
Okay, I got that. Now what’s the equivalent of I6 “found in” in I7? Can I define a “kind of room” with (static scenery) obejcts to look at, or do I have to define them in one specific room and spread them over the other rooms via the equivalent of “found in”?
You need a backdrop (chapter 3.9. in the manual).
Yeah! Thanks!
I discovered that doing tricky things with found_in is problematic in I7. If you need something more complex than a backdrop, you might want to check out my update of John Clemens’ “Conditional Backdrops:”