Entitle can mean to give a title to or to grant legal rights or a just claim to. Although the former definition is etymologically older, the latter definition is now more common (e.g., Employees are entitled to medical benefits). When using the former definition, restrict entitle to the past-participle verbal adjective, entitled. In the transitive sense, use title. Thus prefer The short story, entitled “Stream System” to The short story, titled “Stream System,” and The short story is titled “Stream System” to The short story is entitled “Stream System.”
Through its latter definition, entitled has also shifted into an adjective meaning having privilege, such as The entitled little brat. Although increasingly common, prefer privileged in these cases, as entitled still implies a right or claim to something rather than a subjective state of being.