WordPress Plugin WP Construction Mode Description:
WP Construction & Maintenance mode allows you to hide your entire site, or a specific page while you build and maintain the site. Your visitors will see a beautiful
landing page, with an optional animated progress bar. This plugin is a must-have for every site, because you can use it when you are first building the site, then later
when you are performing maintenance or edits on pages, you can place only the page you are working on under maintenance, and allow your visitors to continue browsing your site as you develop.
Additionally, you can add your Analytics code in the plugin to track how much traffic you are receiving.
Related to WordPress Plugin WP Construction Mode
WPSlug.com data has a list of 106 WordPress CMS installations Using the WordPress Plugin WP Construction Mode.