A splash screen is an image you can see when app or web page is loading. Usually, you see the full screen covered with an animated picture or logo of a specific brand. it is a well-thought marketing approach since it is the start of your first acquaintance with the app loading. As for marketing, you can also be interested in influencer marketing trends for 2018 to promote your product, so mind to read it.
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Today there is no precise information regarding the app that used splash screen first. But it was implemented with a strong reason in mind. A splash screen animation is necessary to take the time required for app loading. Moreover, advanced apps used a more interesting design of splash screen, for example, you could see all files that are loading at this moment. Previously, it was a vital practice since Internet connection was much slower, and, besides that, it has increased users' interest towards new product.