Sometimes, users may receive the following style of emails, claiming expiration, or internet keywords, or domain names, etc.
You may try to search the contact information inside Google, to help you determine the next action.
(F.Y.I. – in most cases, the cases we received (via us and via our customers) are suspected-scam)
In addition, other people do not need to notify you when they want to register (similar) domain names.