title_body: Is there online eBook authoring tool which can produce ePub and PDF formats? I would prefer an online tool so that I am not tied to a particular computer for adding content. Additionally I would expect an online collaboration tool ( distribute chapters to authors and editors) to collaborate with other authors and editors. Exporting to ePub and PDF is a must have requirement.
upvoted_answer: I have heard of 2epub but I have never used it nor would I believe you would get a good quality ebook.  I would suggest doing this with InDesign that will allow you to create .epub or .pdf files.
  
  You can export as an .epub file:
  
  
  
  Export to .pdf file: