WIKIUSERNAME -- your Wiki username with web prefix
Your %WIKINAME% with Main web prefix, useful to point to your TWiki home page
Syntax: %WIKIUSERNAME%
Expands to: Main.TWikiGuest, renders as TWikiGuest
Note: When used in a template topic, this variable will be expanded when the template is used to create a new topic. See TWikiTemplates#TemplateTopicsVars for details