Say you have some Solidity code and something doesn't work and you'd like for somebody to take a look at it and do some quick tests.
What is an efficient way to share Solidity code with others?
A very practical way is to use the gist feature of the browser-solidity
https://gist.github.com/anonymous/b28692c94b053febe27bbb3692bb31ad
Good answer by euri10 already....
If you are just looking for a tool that allows you to send a hunk of code to another person so they can look at it and maybe check your syntax and make some changes, https://codeshare.io/ is a great tool.
It doesn't have Solidity syntax highlighting, but it allows multiple people to work on a single piece of code at the same time, has a short and easy-to-share URL, and is helpful in some circumstances.
Namely, it is great when you are sharing some code with a friend or coworker or two. If you want to post to stackexchange or reddit or something else, using a gist is a more efficient and safe way (as not everyone can edit a gist).