Reading this article I was quite puzzled about the way the author capitalized or not the abbreviations.
When writing in full:
The Internet Corporation for Assigned Names and Number
All words are capitalized, but when abbreviating only the first letter is capitalized:
The Internet Corporation for Assigned Names and Number (Icann)
Following the article, there is an opposite situation:
generic top level domain.
Here, on the contrary the first letter is not capitalized while the rest are:
generic top level domain (gTLD).
Could you please explain if there are some rules on how to capitalize the abbreviations or it’s up to the author’s want?