What are these texts about?

I received one too.  I'd like to know also.

This number is a part of Careers Inc, which is a verification service for employers for hundreds of different job boards. I'm a representative of Careers and would like to clarify why you're getting a text from us on this number. We receive a large quantity of resumes for thousands of positions across the country, and our job is to verify that your contact information is correct. If the information on your resume is invalid, then we help them to correct it and update the employer on the applicant's status. We do not ask for any sensitive information such as SSN. We do not charge for our service. We will never ask you for anything beyond confirming what's already in your resume on file.

Well, I used this site but I never provided my cell phone number, only my home phone. So how did they get my number?