WordPress doesn’t have a maintenance mode. This makes me sad. Luckily, I have a quick fix. First, you’ll need to create a new directory and a temporary “Maintenance” page. For this example, let’s call it /maintenance/index.html. Fill the Maintenance page
Making sure all your guest are coming in through the same url can be important for SEO. Google may see your domain as two sites depending how you use the WWW and non-WWW url. If Google does pickup both your
Here is a simple Gist (originally created by https://github.com/Abban) that lays out all the necessary hooks to start customizing the new ‘Theme Customizer’ in WordPress 3.4