A system that automatically detects references to items like products or brands within messages and replaces those references with referral links to web pages associated with those items. Links may be inserted into a message, such as a text message or email, at a messaging gateway without any action on the part of the sender (or receiver) of a message. Senders or receivers may opt out of or into the link insertion service. The system provides privacy and security because personal information identifying the sender or receiver is not passed to the link insertion service. When the recipient of a message clicks an inserted link and performs a transaction, a referral credit is given to the communication intermediary, and also potentially to the message sender or recipient. The system may analyze modifiers in the message to construct a link to a specific product or service at a website.