When they say 'thought security', what they really mean is the 'influence of deviant ideas', something that began perhaps over a decade ago, but only came to prominence (or was officially recognized here) in 2003 when the attacks by al Qaeda on Western compounds rocked Riyadh.
Up till then Saudis held sympathies for the al Qaeda struggle, seeing it more in terms of Islamic brotherhood or solidarity than 'real' terrorism, but the events of 2003 - 2006 dramatically altered that thinking and brought them, head to head against al Qaeda. With this conference comes an intellectual examination of that struggle and a look at how best to defeat 'deviant thoughts' or extremism in the future. huffingtonpost.com