Max number of files in a folder

see this link
http://support.apple.com/kb/HT2422

Is it dangerous in some way to keep an unusually large number of files inside of one folder with no subdirectories?

No, just don't clutter your Desktop with numerous individual files as it will slow things down. Put them in a folder.

What's the maximum number of files allowed inside one folder in Mac OS 10.4?

2.1 billion. Click here for more information.

Is it larger in later versions?

No.

Is it dangerous in some way to keep an unusually large number of files inside of one folder with no subdirectories?

Having more than 200 items on the desktop at any one time may cause the Finder to become unresponsive. Otherwise, only if that folder's contents are being displayed.

(50498)

Is it dangerous in some way to keep an unusually large number of files inside of one folder with no subdirectories?

In practice I find that a folder I have with approx. 8000 items in it is a bit inefficient in responding. If I do a "reveal in Finder" command from an application to show an item in the folder it will not always actually jump to display the item, although the item is highlighted when I manage to scroll down to it.