Here's what you need to know about ‘coming soon’ signs.
First of all, they can be about a variety of things - property, sales, products, movies etc.
Secondly, these signs must grab attention whilst being completely unambiguous and informative. This is because customers will usually decide something is a waste of time if it doesn't live up to the initial hype or, put simply, back up the strong and "shocking" words with proof.
Thirdly, the sign itself should attract customers from a distance. What's written on ‘coming soon’ signs is usually in red capital letters coupled with exclamation marks and an aggressive design.
Finally, such business signs should not be deceptive or mislead potential customers. Governments across the world usually have advertising guidelines. For example, when selling property, it is common to state on the sign the brokerage representing you together with some contact information.