There are two primary mechanisms for the mass distribution of information throughout the InterNet.
Mailing lists use electronic mail to distribute posts to lists of subscribers.
Each subscriber gets a copy of the posting in their personal mail box. You mail your post to an address which is a mail redistributor program. UseNet news uses its own mechanism to pass articles between cooperating hosts. The articles are stored in a common file system and made available to any and all who wish to read them. Each mechanism has its own advantages and drawbacks.