Multiple modes allows the same keys to do different things in different modes, there isn't much more to it than that.
Say, at a Bash shell prompt in a terminal window, pressing Ctrl+R starts "reverse command search" mode, so that pressing letter keys searches for commands entered in the past, rather than entering a new command. In this mode, up and down move through search results, rather than moving through the entire command history like in "normal" mode.
Lots of software has modes, the unusual thing about Vim is that they have names, and that there is a mode with a focus on navigation.
Why have a mode focused on navigation? Is there something this mode allows beyond navigating? What would be impossible to do if you didn't have this mode?
The keyboard allows you to navigate too, without the need for a mode.
Keep in mind that a lot of the keyboard features we take for granted weren't always present on early terminals. Navigating is a lot harder if you don't have, say, arrow keys. In that case, a separate mode makes a lot of sense for getting around (no arrow keys? Just map hjkl to them in navigation mode). Plus the same command can do different things depending on mode, so there are less distinct patterns of keypresses to memorize. Yes, you could do everything as a series of chords (like in emacs), but I don't think it's necessarily superior.
Here's a list of some navigation mode commands. You can probably come up with reasonable ways to do them with only the keyboard & none of the alphanumeric or punctuation keys used alone, but would that be any easier?
http://www.thegeekstuff.com/2009/03/8-essential-vim-editor-n...
It's used for text manipulation, too - the advantage lies in the fact that the same navigation keys are used to operate on blocks of text. For example, move to the next close-parenthesis can become copy everything up to next close-parenthesis, move to the next blank line can become indent everything up until the next blank line, move to the end of the line can become delete everything up to the end of the line, etc.
(For the record - I think it was a legitimate question. Upvoted!)
I interpret it as a positive sign when someone downvotes without an explanation (live above). It's a sign they don't understand a topic well enough to refute its main point. I'm sorry if the comment above also caused you to grow indignant.
A better response would have been to zoom in at the main argument and say the most important thing there is about it.
If you aren't downvoted enough you are probably not revealing anything controversial.
I'm not sure how true that is and I might be able to prove it.
(1) One way it could help is: if I could get feedback about where I went astray. That's what I want to know when I'm downvoted. I don't care about a karma point, I care about learning something new.
Which makes me wonder: would it help to ask people explain why they downvoted something -- even if their username doesn't get attached to an explanation that becomes public?
(2) Here's an instance where it actually helped: [1]. Me explaining in [2] why [1] was downvoted (which was at something like -1 at the time) lead into [1] being voted again and [2] being upvoted too for clarifying the situation.
(3) This comment is aligned with HN's own request for providing feedback about what's good and bad for HN comments [3].
(4) You should be alarmed when you see a guilty word like "never" used. Particularly if you are the one using it. It's an alarm that indicates you are going to an extreme to justify a position. If what you say is evidently true, you wouldn't feel the need to try hard to qualify it. Or at least, when I made this argument in [4] people voted 20 points for it (which you dang can verify as an administrator).
(5) These arguments suggest reviewing the site guidelines and it's hard to dismiss them as useless. They could improve HN.
I fully understand if what you've discovered studying downvotes is that dealing with them differently leads into more problems than it does dealing with them with the advice of "don't post about being downvoted". I also understand if you are not willing to deal with those problems now. But saying "it never helps" sounds far fetched. You are claiming there's nothing that can be done about downvotes, ever. That's a strong claim to make, especially in a field that's only 50 years old.
Say, at a Bash shell prompt in a terminal window, pressing Ctrl+R starts "reverse command search" mode, so that pressing letter keys searches for commands entered in the past, rather than entering a new command. In this mode, up and down move through search results, rather than moving through the entire command history like in "normal" mode.
Lots of software has modes, the unusual thing about Vim is that they have names, and that there is a mode with a focus on navigation.