title_body: What are the advantages, risks and possible disadvantages of buying ebooks with DRM? What are the 
  
  
  advantages,
  possible drawbacks or
  potential risks 
  
  
  of buying ebooks with DRM (from the readers perspective, compared to non-DRM books)? Is DRM a good or a bad thing for readers? Does it matter at all?
upvoted_answer: The premise in your question's title does not seem to be accurate. E.g. Amazon's terms and conditions state that you don't own the ebook, you buy the right to view it on your Kindle. 
  
  
    All content included in or made available through any Amazon Service, such as text, graphics, logos, button icons, images, audio clips, digital downloads, and data compilations is the property of Amazon or its content suppliers and protected by United States and international copyright laws. The compilation of all content included in or made available through any Amazon Service is the exclusive property of Amazon and protected by U.S. and international copyright laws.
  
  
  Similar conditions apply to DRM-ed material from other suppliers (it probably has to&mdash;but don't quote me on that, I am no lawyer&mdash;as ownership would imply that you can do what you want with something (within legal bounds))
  
  This forms no risk at all, as long as you are aware of this restriction. Unfortunately most people are not, and they speak about buying a DRM-ed ebook and are surprised if an ebook is removed from their device, even if that has happened to many before them (e.g. the erasure of books by George Orwell in 2009; a Kindle being wiped with no explanation).
  
  The disadvantage, IMHO, compared to actually buying a non DRM-ed book is that you are dependent on some software setup to allow you to view material on a specific device. If that device breaks, you might not be able to "activate"
  the content on a newly acquired device if the original provider is not available any more to allow this.