Is it acceptable to nest parentheses?
Is it acceptable to nest parentheses (for example, if I (meaning myself) write like this)?
It is acceptable, but you should use it with care. Generally, you should avoid having long texts in parentheses, as the reader will eventually forget that he is inside a parentheses block.
In serious papers and letters, you should avoid it completely, and rather find a way of re-phrase it.
In conversational e-mails, blog posts, StackExchange posts etc. it might be more natural to use it, but the inner parenthesis should never be long (just a couple of words). The most important is to make sure that the reader don't get confused of where the parenthesis start and end.
Example
With nested parentheses
This is a quick example on how to rephrase a potential problematic use of nested parenthesis. (It can be a less important section like this (which is quite long, even if it is not important), and when you continue, the reader might be lost in where in the parenthesized text he is, and might wonder if he still is inside any parentheses.) Anyway, the main text continues here.
Re-phrased to remove nesting
This is a quick example on how to rephrase a potential problematic use of nested parenthesis.
(It can be a less important section like this. It is quite long, even if it is not important. Now when you continue, the reader is not lost anymore because the long section is taken out in a separate paragraph, and no inner parentheses can be mistaken for an early termination of the outer section.)
Anyway, the main text continues here.
I believe it's acceptable, but vaguely considered poor form, and I tend to avoid it (often by restructuring a sentence and busting out some emdashes) unless I'm intentionally using it to be cute.
Well I do it, but then I spend a lot of time as a mathematician.
If it gets confusing I think using alternative bracket glyphs assists ([{<« »>}]).
[Though using the guillemets (« ») as brackets can get you in to trouble, as a lot of languages use them as speech marks.(Wikipedia)]