The problem: you are writing a paper (using LaTeX, of course) and you need to use a symbol that you use infrequently—maybe the box of the necessity operator. You could look through the main list of symbols for LaTeX, but that document is huge, and you only want one symbol.
A (potential) solution: Detexify. Just go to the page, draw the symbol in the box, and (hopefully) get the code back. (If you use this, click on the right answer to help Detexify learn the right answers.)
I stumbled on this page this morning and tried it out a few times. It worked fairly well, though sometimes my drawings were pretty bad! Check it out if you need a symbol: Detexify.
Detexify in action
Whoa, this is pretty cool. I tried some uncommon symbols that didn’t come up, such as the fish hook for strict implication and the boxed-arrow for counterfactual conditionals (e.g. of Lewis). But actually I think those symbols only exist in obscure packages (well, at least the latter). I’ll definitely use this in the future and see how helpful it turns out.