The phrase "massive billboard" refers to an extremely large and noticeable sign usually placed alongside roads or buildings to advertise products or messages. Full definition
If you want a good example of wasting public money, how about Tower Hamlets PCT's Dept of The Bleeding Obvious advertising on massive billboards:» Spending time with my friends helps me relax»? (conservativehome.blogs.com)
Along with billboards at the side of the highway for restaurants and theme parks, I saw one massive billboard advertising a law firm under the simple but striking strapline: «Hire Aggressive Attorneys». (morton-fraser.com)
They will launch a new advert with the use of a truck with massive billboards on the back, and attract enormous coverage on the news. (totalpolitics.com)