You can get to Trillian for Web's Preferences screen by clicking the gear icon in the lower-right of your contact list:
Play sounds when a contact signs on or off: Uncheck this box if you don't wish to hear when people sign on and off. Play sounds on incoming messages: Uncheck this box if you don't wish to hear a sound when contacts send you a message. Note that contacts can also be set individually. Suspend when closing the web browser: Trillian will keep you online and email you while your browser is closed. Unchecking this box signs you off when closing browser. Automatically display additional URL information on mouseover: Our Instant Lookup feature gives you useful information when you hold your mouse over an underlined word! Language: Trillian is translated into many languages, and our community is hard at work improving the translations and adding new languages. Contact List View: Show entries with tiny, small, medium or large icons. Choose Simple if you don't want to see user icons. Theme: You can change the overall color scheme of Trillian for Web. We've added a special Halloween theme with animation! (recommended only for high-speed computers) Send Diagnostic Log: Press this button if you are working with a developer to resolve a bug. If you have a bug to report, please view our Bug Reporting Guide.