There are many WordPress users who run private blogs and websites which means content comes visible only for logged in users. Same is with BuddyPress, it is now used by various companies, organisations etc for running private networking websites.
JF Simple Coming Soon is the new WordPress plugin you can use for displaying a coming soon or under construction splash page using WordPress visual editor and custom CSS feature.
There are many features in WordPress that doesn’t provides you any admin area setting and option pages. WordPress Helpers plugin opens up those missing settings you wish were there in WordPress and gives you control over them.