Re: . com information
Hello, and welcome to the forums.
I don't know what you mean by that "idiom" either - it's not a standard idiom.
If you mean "dot-com" in general, it simply refers to the industry that is based on the Internet. Online banks, online sites, online everything - the dot-com industry.
If you mean something else, then please post the full sentence in which you read it/heard it. Thanks.
I'm not a teacher, but I write for a living. Please don't ask me about 2nd conditionals, but I'm a safe bet for what reads well in (American) English.