Read Only user

Hello,

I am a newbie to MS SQL server so excuse the newbie question.

I'm trying to create a read-only user in SQL server 2008, I followed these instructions http://www.itsupportguides.com/server-side-tips/sql-management-studio-how-to-create-read-only-users/

after following these instructions, and other posts with similar step by step tutorials, I can log in to the database and I can update tables.

I am not sure if I need to do something more than the instructions above? if so please please help..

Thanks!