Yob Soddoth should be pronounced: “Yob sod off”. ‘Sod off’ is a British form of ‘bugger off’, and ‘yob’ is an old term now almost entirely synonymous to the phrase “English football supporter” (apparently Mark Twain once said: “they are not fit to be called boys, they should be called yobs”). The word probably derives from ‘back-chat’ — a 19th century London thieves’ argot in which words were turned round in order to confuse police eavesdroppers. Not so far removed from Polari, in fact.
At the same time it is also a pun on H. P. Lovecraft’s ‘Yog-Sothoth’, one of the chief supernatural nasties in the Cthulhu mythos (see especially the novelette The Dunwich Horror and the novel The Lurker at the Threshold).
Finally, Ponder and Victor are studying the Necrotelicomnicom in this scene.