Drawing Circuit Diagrams With Circuit Canvas
Drawing circuit diagrams is very easy with Circuit Canvas - even easier than drawing with pen and paper. Just drag the components you need into the Schematic canvas, and click on the pins to draw wires between them.
I often need a simple circuit with 3-4 components to show an idea. Now I'm able to do this in less than 30 seconds.
Once you're done with the circuit, you can export it into various formats (like png or svg) or share it with your friends through the sharing function.
If you mark your project Public, then anyone with the link will be able to see the circuit.

You can also use the very useful function Copy to Clipboard, which creates a copy of the image so that you can paste it (Ctrl-V) directly into an email, a forum post, or your favorite image editing program for further tweaking.
I use this function all the time when helping members learn electronics over at the Ohmify community or when I get questions via email.