These directories are created by programs for various reasons.
When a programs requires a uniquely named directory that the user doesn't need to handle, they tend to use GUIDs, hence the directory names.
Programs typically cannot remember the names of these folders between executions (aka when program closes, it forgets the name), unless they use the registry or a configuration file. It isn't common to do this though. So you can consider these directories temporary.
They can't be stored in the %TEMP% directory because data stored there has no guarantee of volatility, so the program may need to use the data again very soon after saving it. Which means that these directories are used usually by program installations, and sometimes things like telemetry or statistic collection.
In short, you can delete the directories, but there is a very slight risk of screwing up some verybadly written program.
By directories you mean folders, I suppose
Should I leave them alone? They won't take up much storage space, will they, since they are all empty. Will they disappear if I run Disk Cleanup I wonder.
Edwin
curious to an answer
Directories and folders are just different names for the same thing.
The appdata folders are created by applications for their own private use. They can and are used for a wide variety of purposes. There are no firm standards for this, only recommendations and they are frequently ignored. Disk cleanup has no knowledge of or interest in these folders. Disk Cleanup is very conservative (as it should be) in what files and folders it removes. I think it highly unlikely that Disk Cleanup would delete anything in these folders under any circumstances.
There is no way to know for certain what application made these folders or for what purpose. I would guess that they could be deleted without problems but that is only a guess. Such guesses, even by experts, could be very wrong.
I tend to be conservative in what I delete. Others may have different views.
The term "directory" comes from the DOS days when the OS was text based. Now with GUI based OSes they're clickable folders. For example, Command Prompt uses the same system as DOS while Windows is GUI based.