DrawPortal Alternatives

Draw together on a nearly infinite canvas with your friends or with strangers.

Inko › Interactive Whiteboard is an application for apple products where users can create projects on whiteboards by working in collaboration.

Draw and paint live with friends or strangers on a big canvas. There is also a gamemode and gallery.

UMLGraph is a professional automated drawing tool that allows the designers the declarative specification and drawing of UML class and sequence diagram.

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.

Dia is a GTK+ based diagram creation program for GNU/Linux, MacOS X, Unix, and Windows, and is released under the GPL license.

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.

OmniGraffle is for creating precise graphics like website wireframes, an electrical system designs, or mapping out software class.

PlantUML is an open-source tool that uses simple textual descriptions to draw UML diagrams.

ArgoUML, free and safe download. ArgoUML latest version: Open-source diagramming application for personal computers. ArgoUML is a program that allows users to create complex and professional diagrams.

UMLet - Free UML Tool for Fast UML Diagrams

StarUML

Gaphor is a Python-based, open source, multiplatform and multipurpose modeling application for creating nice UML diagrams for documentation.