Folks new to email will probably follow the default style for their mail reader.
Likely to be this...
....or this next example (below) which shows your reply (in blue) on top of
the original message.
The third option, which people learn about just be experimenting, or by reading about email posting etiquette, is 'point by point' replies.
( The official term for what I have called 'point by point' is inline replying also known as 'interleaved' )
If you reply style looks like neither of the above pictures, then you already know what I am talking about.
Why do some folks object to 'Bottom posted' replies? (first example above)
Unedited 'Bottom posting' means that if the original message was long and it is quoted in entirety, then there is much scrolling to get to what you now say in reply.
Editing (snip) and using ellipsis (...) can help the reader of your reply just see again the important bits of the original message, to which the reply points apply.
People object less to both of the styles shown above, when snip and ellipsis are used in this way.
If the person objecting uses a mail client that adopts a different default, then the objection might be nothing other than their own frustration at not knowing where to change the 'reply style'
Why do some folks object to 'Top posted' replies? (second example above)
Early netiquette suggested that 'Top posting' was to be avoided.
On iterative replying systems (mailing lists), it helps to not have the style chopping and changing throughout the thread. If your mailing list is bottom posted (probably), then you should stick with that style and know the 'reply style' option for you mail reader.
In Thunderbird the option is located at ...
Edit -> Account Settings -> Composition & Addressing
and the choices available are ...
Automatically, quote the original message when replying and then, ...
- start my reply above the quote
- start my reply below the quote
- select the quote
- none of the above (leave the overall checkbox unticked)
( The last option is for those who prefer to not quote the original message at all. )
Other options 'point by point' (inline / interleaving)
Point by Point is something a mail client can 'assist' with but the actual final form is very ad-hoc and under your manual control.
Use 'select the quote' in Composition & Addressing, to help you bring across something suitable to 'interleave'
and now with 'select the quote' option in effect, your reply brings across (by default), the entire original message and it is 'selected'
Pressing the delete key will just delete everything, and is your easy way of including none of the original message in your reply.
Another useful way is to select the portion of the original message before pressing 'Reply' in the first place. That way you are 'selective quoting' as shown below:
Here I highlighted some of the third line of the original message, and then hit 'Reply'.
My reply has brought in just that small portion of the original message for me to work with :)
Either of the above 'select the quote' ways I described, are how you might begin 'point by point' replying. Adapt your approach as you see fit.
Notes and Further reading:
Being flexible about the style of reply which you accept will prevent you alienating new people you socialise or work with via Email at work or at home.