Flowcharts has real potential. I am sure that there will have been a lot of hard work bringing the site this far. There are some strong draw features, such as alignment, gradients and line types as well as a large clip art bank to draw from. Some interesting collaboration and export options.
Its a little slow rendering at the moment and maybe one or two visio-structural improvements to be made but all in all, it was not to taxing to produce my first flowcharts, chart.
A couple of points, if the menus are unseen, look under your browser toolbars (View / toolbars). If you find it hard to find a function, simply holding down CTRL brings up the shortcut menu (a neat idea I thought). While there maybe offline tools out there, like the aforementioned SERIF Draw Plus X2 package, this site does permit the collaboration of all good web apps.