To sign up to have copies of a publication, such as a newspaper or a magazine, delivered for a period of time.
To pay for the provision of a service, such as Internet access or a cell phone plan.
To believe or agree with a theory or an idea (used with to).
To pay money to be a member of an organization.
To contribute or promise to contribute money to a common fund.
To promise to give, by writing one's name with the amount.
To agree to buy shares in a company.
To sign; to mark with one's signature as a token of consent or attestation.
To write (one’s name) at the bottom of a document; to sign (one's name).
To sign away; to yield; to surrender.
To yield; to admit to being inferior or in the wrong.
To declare over one's signature; to publish.
To indicate interest in the communications made by a person or organization.