I'm going to show how you can create stencils without using other drawing tools.

Please watch the following video first:

Basic steps, such as saving the diagram as "Stencil", are the same as what you've seen on "How to Create a Stencil" tutorial video.
In this way, you don't need to export as SVG from other tool and import into Cacoo. It will be easier for heavy Cacoo users as all procedure of creating stencils can be done on Cacoo.

Expressing details will not be as good as drawing on Illustrator but with your creativity and ingenuity, you'll be able to draw more complicated drawings on Cacoo.
I've created a camera stencil on Cacoo this time. I believe that it's good enough for using as an icon on websites.

Illustrator is not a must have. You can create attractive stencils using Cacoo only. Enjoy!