A method of broadcasting messages to everyone who is interested in a given narrow topic. There are currently about 4000 topics. Only one copy of the message is sent to each computer supporting people interested in that topic. In contrast, a mail list would send individual copies to each user on the list. Usenet topics are for large global, public, communities of interested users.
Mail lists are for smaller private groups.
Usually called newsgroups . Web files don't have the length counts. Not null terminated. UTF is an external format. Unicode-2 supports even 32 bit characters, and UTF has been extended to handle them as well.