10.9.5 Composing messages

• [5.1]: What are the basic commands I need to know for sending mail and postings?
• [5.2]: How to enable automatic word-wrap when composing messages?
• [5.3]: How to set stuff like From, Organization, Reply-To, signature...?
• [5.4]: Can I set things like From, Signature etc group based on the group I post too?
• [5.5]: Is there a spell-checker? Perhaps even on-the-fly spell-checking?
• [5.6]: Can I set the dictionary based on the group I'm posting to?
• [5.7]: Is there some kind of address-book, so I needn't remember all those email addresses?
• [5.8]: Sometimes I see little images at the top of article buffer. What's that and how can I send one with my postings, too?
• [5.9]: Sometimes I accidentally hit r instead of f in newsgroups. Can Gnus warn me, when I'm replying by mail in newsgroups?
• [5.10]: How to tell Gnus not to generate a sender header?
• [5.11]: I want Gnus to locally store copies of my send mail and news, how to do it?
• [5.12]: People tell me my Message-IDs are not correct, why aren't they and how to fix it?