If the existing sales tax permit was issued to the same company - and you do not have retail locations - you may use the same permit.
While such services are not taxable in most states - they are taxable in TX - please see for reference this publication - http://www.taxadmin.org/fta/pub/services/rr147srv.pdf - page 28 for computer related services in TX.
See also these publications - Data Processing Services are Taxable and
Information Services
Let me know if you need any help.
Based on your description - I would classify your services as Informational services - not as marketing services.
So the real question is how to classify your services.
If you have a question on a specific service classification - you might want to confirm that your classification agreed with Texas Comptroller
call toll-free number 1-800-252-5555,
or email at XXX.XXXX@XXX.XXXXX.XX.XX.
Tax Preparer
Taxes, Immigration, Labor Relations