Advertising is a paid promotion that uses strategic planning to target a certain audience. The seven functions of marketing is promotion, selling, product management, marketing information management, pricing, financing, and distribution. Usually you see common advertising such as digital ads, billboards, newspapers, flyers, and more. Advertising can spread awareness, popularize a brand, increase customer demand, and company profits. Advertising is necessary for most- if not all- companies including media outlets, the television industry, search engine companies, and social media websites.
TCP is a reliable protocol. Verification of the data (to an extent) is performed. UDP is an unreliable protocol. It's a "fire and forget" protocol. Since the verification ( packet counts, checksums ) isn't being done, the application[s] have to do it.
You can easily find and changed the data by using lookup table. You can also find the data within few seconds.