From a product or service: This is a redirect from a title that is the name of a product or service to a more general, relevant article such as the company or person that sells it.
This redirect leads to the title in accordance with the naming conventions for common names and can help writing and searches. It is not necessary to replace these redirected links with a piped link.
To a related topic: This is a redirect to an article about a similar topic.
Redirects from related topics are different than redirects from related words, because a related topic is more likely to warrant a full and detailed description in the target article. If this redirect's subject is notable, then also tag it with {{R with possibilities}} and {{R printworthy}}.