Software:

 Photoshop
 Lawson
 Flash
 MS Office
 Windows
 Outlook
 Paintshop Pro
 Shareware
 Freeware
 System Utilities
 Tips
 Updates
 Reviews
 Software
 Emulation
 Development
 Graphics
 Operating Systems

Music:

Alternative
 Artist Promotion
 Composition
 DJ
 Education
 Electronica
 All Genres
 Instruments
 Jazz
 Labels
 MP3
 Rap/R&B
 Musical Theater
 Production
 Punk
 Raves
 Rock & Pop
 Theory

News & Information:

 World News
 TipWorld
 Journalism
 Religious Information
 Newsletters
 Newspapers
 General Resources
 Media Ethics
 Organizations
 Web Site Updates
 Science News
 Horoscopes
 Jokes
 Trivia
 Technology News
 Entertainment News
 Health & Fitness News
 Computers & Internet News

Books, Movies & TV:

 Directors
 Filmmaking
 Book Reviews
 Videos
 Sacred Texts & Commentaries
 TV Shows
 Poetry
 Sci Fi, Fantasy & Horror
 Children's Programming
 Actors & Actresses
 Movie Reviews/Promotion
 Authors
 Television
 Books & Literature
 Movies & Film
 Public Television
 Book Clubs
 Networks

Developers:

 Java
 Programming Languages
 Perl
 Visual Basic
 HTML
 Web Design
 Web Development
 Webmasters
 System Administration
 Information Systems
 Information Technology
 Computer Science
 Software Development
 Databases
 Programming Tools
 System Utilities
 Security & Encryption
 Data Formats

Sports & Recreation:

Sports- General
 Outdoors
 Soccer
 Gardening
 Baseball
 Golf
 Hockey
 Cycling
 Watersports
 Football
 College Sports
 Snow Sports
 Martial Arts
 Production
 Plants
 Autos
 Motorcycles
 Auto Makes & Models

Travel & Leisure:

Travel
 Adventure Travel
 Air Travel
 Budget Travel
 Cruises
 Destinations
 General Resources for Travelers
 Leisure Travel
 Lodging & Resorts
 Motorcycle Travel
 News
 Animals & Pets
 Regional & Travel
 Countries
 Regions
 Travel Newsletters
 Wilderness & Survival Training
 Video Games

Personal Finance:

 Banking & Finance
 Personal Finance
 Stock Markets
 Investing
 Financial Services
 Venture Capital
 Insurance
 Accounting & Auditing
 Credit & Debt
 Mortgages & Home Loans
 Financial Aid
 Stocks
 Investment Clubs
 Mutual Funds
 Business Newsletters

Women & Family:

Mothers
 Families
 Parenting
 Pregnancy
 Children's Health
 Reproductive Health
 Weight Issues
 Single Parents
 Women in Technology
 Women's Health
 Marriage
 Women's Studies
 Women
 Childcare
 Genealogy
 Domestic Partners
 Women in the Arts
 Women in Business

Personal Technology:

 Hardware
 Servers
 Personal Digital Assistants
 Digital Cameras
 Peripherals
 Personal Computers
 Macintosh Computers
 IBM
 Assistive Technology
 Technology
 Women in Technology
 Web Cam
 Scanners
 WebTV
 Computer Games
 Consumer Electronics
 Technical Support

Small Business:

 Small Business
 Home Business
 Telecommuting
 Careers
 Entrepreneurship
 Consulting
 Employment
 Human Resources
 Recruiting
 Ethics
 Management
 Business Law
 Business Development
 Electronic Commerce
 Socially Responsible Business
 Consumer Affairs
 Import/Export
 Products & Services
 Biz Opp Seekers
 MLM

Health & Fitness:

 Health & Fitness
 Addiction & Recovery
 Children's Health
 Fitness
 Healthcare
 Medicine
 Mental Health
 Support Groups
 Alternative medicine
 Diseases & Conditions
 Personal Growth
 Reproductive Health
 Weight Issues
 Men's Health
 Women's Health
 Aging
 Environmental Health
 Holistic Medicine

Internet:

 Internet
 E-Mail
 Chat Groups
 IRC
 Internet Gaming/Casino
 General Resources
 User Groups
 Domain Registration
 Website Reviews
 Website Updates
 Internet Companies
 Organizations
 World Wide Web
 Webmasters
 News
 CGI (Common Gateway Interface)

Free Targeting Options :

 Gender
 City
 State
 Country

Additional selects:

Age
Income
SIC CODE
Business Type
Employee Count
Zip
County

If you can't find a target audience in these catagories you can also send to a general list of opt in emails.