Based on this (and a few other) reviews, I'm not entirely sure how this book is supposed to be different from Foucault's Pendulum.
Numero zero, on the other hand, reads like some long form notes hastily out together to resemble a short novel. The book is fast, lacks action (as noted by the review) and in the end really seems unfinished or unproperly edited. It certainly wasn't something you'd expect from someone like Professor Eco. Plus, the plot and the setting are completely out off time and focus on a period - the 90's, or the late Wild West of media control by Berlusconi and his accolades - that's obsessing Eco for some time, along with the fact that he's more comfortable writing about the mechanics of old media that he, on some level, misses dearly.
You are correct in mentioning that it is "not too different" from Focault's Pendulum. Let say that while F.P. was mostly about esoteric sects and the people who believe in supernatural, this one is more about conspiracy theories (Italian post-war history and politics are full of events that have never been explained in a satisfactory manner) and how media can use "information" no matter if it real or fabricated, to bargain for power.
The meta-themes about real and fake might be universally interesting, but I wonder if the book can really be enjoyed by readers that have not been living in Italy for at least two decades.