Yes. I used to get nearly all of my programming information from books or at least tutorials. Now I get nearly all of it just from resources scattered around the web.
These are bit level errors. So instead of losing a bit or two, you lose a massive chunk. That's the difference between a strange character in your Doc file and losing the whole thing.
I think it's 128 bits for truecrypt, although internet searches point to many people using higher (1024 and 4096).
And if the bit level error rates are as high as he says, looks bad.
No, but it will notify you of a problem. However, I suspect that smartmontools would do an even better job of notifying you of a problem before it even occurs.
If you want something that will actually protect against bit level errors well, generate some extra data using an appropriate Error Correcting Code for your important archives/files. Something like what par2repair generates. This is incredibly slow compared to simple erasure codes like RAID uses, though. There are some filesystems that do this for you automatically, I wrote one:) Actually, other than that I don't know of any filesystems that do this.
If the above is impractical for performance reasons, Google recommends mirroring everything on three disks...