[PLUG] How to ask question ONLY loosely related to another thread?

[Richard Owlett]

In a thread titled "Emacs text modes", Russell Senior wrote:
> You can look for files that might have changed, say, in the last 7
> days, in your home directory tree with something like this:
> 
>   find ~/ -type f -mtime -7 -printf "%T@ %p\n" | sort -n | less

"How to ask question ONLY loosely related to another thread?" is really 
two separate questions:

1. This post is an example of one in which quoting a portion of
    a previous post gives *all* the context required to answer
    the question(s) posed.

2. A second situation is where the previous post doesn't/can't
    provide all the context required to answer the question(s) posed.
    The temptation in this case is to "hijack" the previous thread
    by starting a sub-thread (perhaps with a different or modified
    subject line).
    IOW, how does one link to the previous thread so a potential
    respondent can conveniently know the total context?

P.S. Questions raised by Russell's post are coming ;}