The most common set of questions in the newsgroups asks about the difference between Visio Standard and Visio Professional. For Visio 2007, Microsoft has published a handy guide detailing the differences between the two editions. There are breakdowns by feature and by diagram type.
There are a couple points worth making here. First, for those using the Visio that ships with Visual Studio for Enterprise Architects or Visual Studio Team System, there is no Visio 2007-based version as of yet. The latest Visual Studio offering includes Visio 2003.
Second, this is the first release where some features of the Visio engine are only available in Visio Professional. For those unfamiliar with Visio's archictecture, the product consists of a drawing engine plus lots of content (shapes and templates and add-ons) that work with the drawing engine. Historically, the drawing engine is the same in every edition and only the content varies by edition. In Visio 2007, the features related to data connectivity (Data Link, Data Graphics, Data Refresh) are only supported in the Professional edition. As in previous versions the Professional edition also has additional content.
Visio 2007 Standard can open files created in Visio 2007 Professional, but the data features are disabled. This delineation extends to Visio's programming interface. Automation related to the new data features will not function on Visio 2007 Standard. This behavior is somewhat akin to opening files in Visio 2003. While Visio 2003 and Visio 2007 share the same file format, Visio 2003 does not have the new data connectivity features. For example, in Visio 2003 you can work with a 2007 diagram that contains Data Graphics, but you cannot apply a data graphic to another shape or manipulate the existing data graphics.
Thanks to all our MVPs and newsgroup responders who answer questions about Visio's product editions. Now you can point them to the new Office Online link.