What are some alternatives?
When comparing asciiflow and Diagram Designer, you can also consider the following products
Charaster - Open-source ASCII art editor for browser-based, raster-style editing
LucidChart - LucidChart is the missing link in online productivity suites. LucidChart allows users to create, collaborate on, and publish attractive flowcharts and other diagrams from a web browser.
Playscii - Full-featured ASCII art and graphic editor and game creation tool
draw.io - Online diagramming application
Ascii Generator 2 - Ascii Generator 2 (Ascgen2) is an application to convert images into high quality ASCII art - text...
yEd Graph Editor - yEd is a free desktop application to quickly create, import, edit, and automatically arrange diagrams. It runs on Windows, Mac OS X, and Unix/Linux.