I finished this earlier this week (actually, I've read lots lately, and just haven't been keeping up on my posting) and loved it. I wasn't surprised, since I loved American Gods as well. And Coraline, for that matter.
Neil Gaiman does an amazing job of making poor Fat Charlie sympathetic, even while he does things that are so frustrating to the reader... it's a good way to get a reader hooked and interested. Fat Charlie bumbles his way through and the reader is given enough clues as to who everyone is (because it's almost never clear to Fat Charlie) and what they're really up to (because Fat Charlie misses all of that too) that it works. There's action, adventure and romance, and all within the crazy idea that Anansi had a child and then all kinds of misadventures happened to the one who missed out on the god-like powers.
Knowing as little as possible about the plot is an advantage to the reader, and makes the ride that much more enjoyable. Anansi Boys is funny and interesting, while capturing the sense of mystery of the old stories.