Q:

What about overview of basic LaTeX commands here in meta? 

I have feeling that something like this has been asked before, but I cannot find such post, so my memory might be fooling me. 
Do you think that giving here examples of usage of the most frequently used LaTeX constructions here at meta could be useful for our users?  I tried to write down something for integrals here: How to show the integral symbol on this site? 
If you think that this would be a good thing, what topics to you think should be covered. 

A:

If we decide to do something like this, I like the way LaTeX help is organized at sosmath, so I would go with something similar to their help:

Basic commands (superscripts, subscripts, bracket for sets $\{\}$, inequalities $\le$ and similar stuff that is frequently used, but does not fall nicely into other categories; \operatorname and \text could be mentioned here)
fonts and some frequently used symbols (like $\pm$, $2\mid4$, $2\nmid 3$, $\infty$, $\vec{a}$)
alignment and multiline formulas (perhaps also difference between inline math and centered formulas could be explained there)
polynomials, radicals, fractions
Greek letters
trigonometry
limits
sums
derivatives
integrals
matrices
sets, operation with sets ($\cap$, $\subseteq$, $\bigcup_{n=0}^\infty$ and similar stuff; notation for intervals - $[a,b]$ or $\langle a,b \rangle$ but not $<a,b>$)
(maybe) combinatorics (also from the top of my head I can only think of binomial coefficients, so this might fall under frequently used symbols)
(maybe) tables (array, \hline, etc.) 
(maybe) elementary number theory (divisibility, congruences, Jacobi symbols)

