Visual thinking is probably most effective when using a suitable methodology as an aid to construction and communication. Simply said
Visual methodology = visual language + rules of thumb
This set descends from the non-visual Issue-based information systems (IBIS) methodology, and is suitable for activities including Dialogue mapping when working in a group or facilitating a meeting, and Issue mapping when working solo.
An example of another visual language / methodology is the set of boxes and templates that we designed for use with bSelling, based loosely on the non-visual Solution Selling methodology (and simplified a good deal):
So different visual languages work better for different purposes.
Rationale is mainly built around a visual language for argument mapping; bCisive has several; with bCisive Online we plan to offer the possibility of organization-tailored visual languages plus templates.