Caswell.org

Here are a few of my favorites. Let me know if there are others you would like to see added:

AllTop Economics - Aggregator of economic news from the web
AllTop Real Estate - Aggregator of Real Estate news from the web
BEA - U.S. Economic Data
Argus Software - Global leader in Commercial Real Estate Software Solutions
Blackbook Online - Directory of Public Record Directories.
BLS At a Glance - U.S. Employment Data
Boxwood Means - Sales Comps for smaller transactions
Bureau van Dijk - Corporate Databases - particularly strong for non-U.S. entities
CB Richard Ellis - Commercial Real Estate. Global market coverage
CBRE Econometric Advisors - formerly Torto Wheaton Research/TWR. Econometric forecasting and data.
CCIM - education and networking
Census Bureau - U.S. census data
ClientLook - software to increase broker activity communication
Colliers International - Commercial Real Estate. Global market coverage
Commercial Mortgage Alert - Current and recent history on CMBS markets
The Conference Board - Consumer Confidence and other indeces
Costar - Property, tenant, and transaction data
Cushman & Wakefield - Commercial Real Estate. Global market coverage
Dismal Scientist - News and Analysis from Moody's Economy.com
DOL - U.S. Employment Data
The Economist - News
Economy.com - Economic data and forecasts
Emporis.com - Global property data, images, and standards
ESRI - Mapping and Demographic software and data
FactivaDow Jones news and company data
First American Corelogic - Ownership data
GeoVue - Mapping and Demographic software and data
Global Insight - Economic data and forecasts
Google Maps API Documentation
Google Earth API Documentation
Green Building Finance Consortium - Report Library from industry thought leaders
Grubb & Ellis - Commercial Real Estate. U.S. market coverage
Hanley Wood - Multi-family property data
Harris Selectory - Easy to use access to D&B Company data.
Hoovers - Easy to use access to D&B Company data.
Jones Lang Lasalle - Commercial Real Estate. Global market coverage
Leo Software - Property Database software
Lexis Nexis - News and company Data
LoopNet - Listings of properties available for sale or lease, and sale transaction data.
MapInfo - Mapping and Demographic software and data
McGraw Hill Construction - Data on planned projects, now sold through CBRE Econometric Advisors
Metrostudy - Multi-family property and land data
NAIOP - Education, Research and networking
National Cadastral - Mapping the U.S. and extending standards
NCREIF - data and reports on a set of U.S. properties
OSCRE - Standards and networking
Pictometry - Oblique aerial imagery
Pierce Eislen - Multi-family property data
PKF - Hospitality Forecasts and data
PopStats - monthly updated demographic data
PPR - Econometric forecasting and property consulting.
Property Finance Europe - news and information on European property markets
RCA - Global Commercial Real Estate Sales data
RealFacts - Multi-family property data
REIS - U.S. Commercial Real Estate data
RS Means - Construction data and tools
SalesGenie - Company Database
SIOR - Education and netowrking
Smart Scholar - Economics Education Resource Guide
SNL - Data on REITS
SRC - mapping and site selection software - now called Alteryx
Thomson Reuters Deal League Tables - Useful data on debt and equity public markets
UBS Investment Research
Wall Street Journal Economic Forecasting Survey
Wells Fargo Research
Xceligent - Property Data Software for Local Market Exchanges