Prove that you care for web standards. Use simple HTML 4 for output instead of pretending you know what XHTML really is.
Standardista is a set of options for Haml 2.0.
Include the Haml gem in your environment.rb:
config.gem 'haml', :version => '~> 2.0'
- sets Haml output to HTML 4
- in production: sets Sass output to 'compact'
- in production: turns on Haml 'ugly' mode (faster rendering because it doesn't care for indenting)
- patches ActionView
taghelper to stop generating self-closing tags
More to come.