Someone may have been trying to sue you by notifying you by publication and if a judge approved it, it is presumed valid. I would get a lawyer and get on it right away, you could be losing rights as we speak.
There are a number of different methods to serve someone under Oregon law, and service by publication is one of them. Typically, service by another method, like by hand or mail, is attempted first. But in cases in which a defendant is proving to be hard to find, service by publication can be permitted. And, often times, defendants will actually be notified of such a suit, as you were, in the case of publication.
*Disclaimer: This is not legal advice; please do not consider it as such.*