Search This Bbook relies on the Search Indexes in the system/ folder.
On my Kindle Touch, books usually take a little while to index, but I've never had a book fail to index after a while.
Usually when downloading from Amazon, a book is immediately searchable -- I suspect Amazon has pre-made indexes.
As for About This Book, I don't seem to have that on my Kindle
but I know other stuff like X-Ray, About The Author, etc. depend on (are sourced by) files in the ancillary *.sdr/ folder, which will eventually be downloaded from Amazon's servers. calibre makes no effort to create these.
Perhaps About This Book does the same thing.
I believe I heard mention about a new feature that shows metadata -- series, comments, etc. -- without needing to go through the Kindle Store. Is that what you are talking about?
I wouldn't be at all surprised if Amazon decided to use yet more random data files rather than the ebook metadata.
