The demand for web-based applications plus the need for online collaboration plus the amazing web interfaces that can be created with new technologies (e.g. HTML5 canvas) has created a “new” market for modeling tools: online modeling tools. In fact, they are more drawing tools than modeling tools but still, they at least offer you a way to draw and share your (UML/ER/BPMN) models online.
If you want to give them a try (most offer a free plan or at least a free trial), the five tools I’ve been more looking into (let me warn you, don’t expect me to declare a winner, just decide by yourself!) are, in alphabetical order,:
Online diagramming and collaboration. Several modeling languages supported (including UML). For a short introduction see the presentation of this tool for the portal readers in a guest post by Creately authors , see here
Pure HTML5 Online Flowchart Software, licensed under GPL (nice!), which obviously means that you can also have the option to install it on your own server. The only “but” for the typical readers of this portal is that as a flowchart-focused software, it only covers one kind of UML diagrams: state machines (but there is an easy solution for this just fork it on Github and extend it yourself 🙂 ). Diagrams can be easily shared with others but synchronous collaboration is not possible.
Fails in the collaborative aspect and it’s less feature-rich than the others but I love its simplicity. All you see is a empty canvas ready for you to start drawing. Support for BPMN notation.
Support for UML and BPMN diagrams (among many other types). They claim to be “the most widely used online diagramming application”, I wonder how they know that. Collaboration and revision control features available.
Flow charting tool with support for all major UML diagrams (and also BPMN). The tool has a demo mode you can use to try it for free. Works also when you are offline and there is a desktop version available so you can choose.
HTML5-based. With UML support and real-time collaboration capabilities. It can import Visio files, which is definitely a plus considering that all these tools seem an online version of Visio and are probably targeting the same kind of users.