It is worth noting that recently courts have said that failing to conduct a reasonable search prior to adopting a mark is sufficient bad faith to be held liable for monetary damages. Thus, trademarks are, in essence, monopolies facilitated by the government. They are monopolies over the use of symbols in business. A trademark owner can exclude all other businesses from using a similar mark on related goods or services. They allow businesses to build an identity and reputation with customers, and thereby grow or expand.
Trademarks also allow individuals to be better consumers.
In fact, Trademark law is the original consumer protection statute. It ensures that consumers can repeat their positive buying experiences by searching out familiar brand names, and avoid bad buying experiences by steering clear of brands they didn't like. It appears to be common usage to refer to service marks as either trademarks or service marks. Some trade names are also used in a way that makes them trademarks as well. If they use the former, then ACME remains a trade name only.