Shi'ism: the ultimate conspiracy from you-know-who

Did you know that some Sunni Muslims believe that Shi'ism is a Jewish plot? Here is a sentence from yet another recent post from MPAC.ie, attacking Shi'ism and citing what they evidently see as a particularly damning fact:

The religion of the Shia’ was founded by a Jew from Yemen called Abdullah bin Saba’ and spread after with the assassination of the rightly guided Khalifa Uthman, branching into many sections.

According to something called allaahuakbar.net:

. . . when the Jews were convinced they are unable to halt the fast growing and spreading of Christianity by means of force, they planed to destroy it from within. This mission was successfully carried out by Rabbi Paul. When Islam came, likewise, the Jews again attempted to abort this new religion. Their endeavors took many forms and shapes, from attempts to assassinate the Apostle of Allah [saw] to waging wars that ended in deporting most of them from al-Madinah or executing those who betrayed the truce. Similarly, they were convinced that the best way to destroy Islam and the Muslims' unity was to resort to the plot they used with Christianity. A Yemenite Jew by the name of Abdullah bin Saba' , as Paul did, pretended to have embraced Islam to plant secretly the seeds of this new cult which he successfully performed.