1. Web
   1. front-end
      1. HTML
      2. CSS
      3. JavaScript
      4. AJAX
      5. YUI
      6. Flash
      7. Performance optimization
   2. back-end
      1. PHP
      2. PHPTAL
      3. ASP
   3. CMS
      1. Joomla
      2. MediaWiki
   4. servers
      1. Apache
      2. Memcached
2. Win
   1. languages
      1. C
      2. C++
      3. C#
      4. VB.NET
      5. VB6
      6. VBA
      7. Access
      8. Delphi
      9. Java
   2. domains
      1. DB applications
      2. Data acquisition
      3. Project management
      4. Data visualization
      5. Protocol testing
3. DB
   1. MySQL
   2. SQL Server
   3. Access