Five free apps for creating diagrams in your browser
Creating great-looking, eye-catching diagrams is a fairly simple task these days, thanks to all the software available on the market. However, most of these packages carry a price tag.
Luckily, several free diagramming apps are available, and you don't even need to download anything. Here are five free, web-based tools you can use to create different types of diagrams.
Note: This gallery is also available as an article.
I am using balsamiq for quite some time and it's a superb application as well on browser to draw the wireframes of your application or your network and many more.
You missed one of the best: http://cacoo.com
Cacoo IMO blows these others out of the water. I've used it for years and collaborated remotely on diagrams with colleagues using it. It exports to free .png format and with various subscription level to advanced formats (pdf, ppt, svg, ps, and png). You can create your own templates, use their wide free selection, or purchase templates via their marketplace. The free tools, however, are awesome and usually get the job done. They also offer non-profits and education team accounts (free trial - one I had lasted 6 months but check site for updated terms).
And for mind mapping - also with collaborative features and various export formats (free and subscription): http://mind42.com