Allplan
Nemetschek, Allplan Reading Room, Allplan Users Pages, CAD Consulting USA

ArchiCAD
Graphisoft US, ArchiCAD Reading Room, arkiKlub, Pacifico, GDL Cookbook

Architectural Desktop
Autodesk, ARCHIdigm

Ashlar-Vellum
corporate site, Web-based tutorials

AutoCAD
TopTen sites, add-ons, blogs, Civil 3D, services & consultants, shareware, training, tutorials, tips and tricks, user groups, VBA

AutoCAD LT
Top Ten sites, add-ons, reviews

Autodesk VIZ
Vizdepot

CADVANCE
FIT, Inc

DataCAD
TopTen sites, dealers, reviews, training, users groups

DesignCAD
DesignCAD Unleashed, CADdigest.com, Upperspace

General CADD
corporate site, user forum, CADdigest.com, CaddVillage, Astec Computing

IntelliCAD
IntelliCAD Technology Consortium, IntelliCAD Reading Room, Bricsnet IntelliCAD

Intergraph
TopTen sites, TopTen SmartSketch Sites

Land Development Desktop
Autodesk LDD site

MCAD User Communities
CADKEY, CATIA, Inventor, Pro/E, SolidWorks, Unigraphics

MEDUSA
CAD Schroer, COMSA 

MicroStation
TopTen sites, consultants and training, downloads, forums, magazines and newsletters, MicroStation V8, 3rd party tools tutorials, user groups

Rhino
TopTen sites, blogs, communities, 3rd party tools

Revit
TopTen Sites,
products

SketchUp
TopTen sites, libraries, productivity, rendering inside, rendering outside, viewers, workflow

TurboCAD
TopTen sites, reviews, 3rd party tools

User Groups
AutoCAD, CATIA, Mentor, MicroStation, Pro/ENGINEER

VectorWorks
Nemetschek N.A., Objects Online, 

Visio
Visio, Design-Drawing, Visimation

Visual CADD
VCADD User Group, TriTools, VisualCADD.com