IDN.IDN is an abbreviation for an Internationalized domain name whose Top level domain (TLD) is also internationalized, which could be transliterated .com, .net, .org, etc. or be groupings relevant to the language at hand.
Chinese:
Korean:
Japanese:
Russian:
Hebrew:
שלום.דבר : shalom.dbr (dbr being roots of the verb 'to talk')
דפנה.שלי : daphne.shli (shli being a preposition 'of me,' for personal homepages, etc.)
Arabic:
كوم : .com
نت : .net
اورج : .org
Concerns and considerations
As this is an issue still being "decided upon," (for many years, apparently) there are many factors to be considered. Here are a few just thrown out to be edited around and made to look pretty.
IDN.COM vs. IDN.IDN, important issue as IDN.COM is already available.
Compatibility
Punycode
"branching off from the *main* internet" (various POVs)
Who Owns The Internet
The UN Resolution from meeting in Tunisia
Localization
Transliteration of COM NET ORG vs. culturally significant TLD names of the languages' own choosing.
Right-to-left formatted languages such as Arabic and Hebrew
