Originally Posted by Notjohn
Well, not entirely useless! It serves as an excellent sales tool when seen on Amazon's Look Inside and Barnes & Noble's Read Instantly Feature. I assume (well, I hope) that other retailers have equivalent previews.
For one, Amazon don't sell epubs, and their Kindle conversion tool all but requires an inline TOC
JSWolf seriously dislikes html TOCs. While I agree with him that they're superfluous in epubs as proper software* should make the toc.ncx available, I just shrug and skip past them whenever I encounter them. Some users like them, and it's not like they're in your way when you read the rest of the book. It's not really hampering the readers who don't use them. (unless you backlink from every freaking headline, as I've seen in a couple of epubs. That *does* irk me). That said, I don't include them in the epubs I make unless specifically requested by the author even after I explain why they're not needed.
* This includes the web pages of Epub vendors who provide a "peek at the book" feature as well, they should really provide a preview of the embedded TOC.