layout.haml

!!!
%html{:xmlns => "http://www.w3.org/1999/xhtml"}
  %head
    %meta{:content => "text/html; charset=UTF-8", "http-equiv" => "Content-Type"}/
    %title #{@title}/
    %link{:href => "css/style.css", :media => "screen", :rel => "stylesheet", :type => "text/css"}/
    %link{:href => "css/contentlayout.css", :media => "screen", :rel => "stylesheet", :type => "text/css"}/
    %link{:href => "css/voice.css", :media => "screen", :rel => "stylesheet", :type => "text/css"}/
    %link{:href => "css/home.css", :rel => "stylesheet", :type => "text/css"}/
    %script{:src => "js/application.js", :type => "text/javascript"}/
  %body.yui-skin-sam
    #container
      .wallpaper
        .topheader
          .logocontainer
            %h1.logoImg
              %a{:href => "/index"}
                %img{:alt => "", :src => "images/logo1.gif", :title => "Logo"}/
          .menu
            .TopMenu
              %ul
                - @menu.each do |m_item|
                  %li
                    %a{:href => m_item[:url]}
                      %span= m_item[:title]
          .searchBox
            .float
              = "Welcome, #{@user} |"
              %a{:href => "/logout", :only_path => "false"} Logout
        =yield

why generate a string in line 28
= "Welcome, #{@user} |"
as opposed to
Welcome, #{@user} |