Is it OK to delete pages and republish the same or similar content on different urls?

Selected answers from the Dumb SEO Questions Facebook & G+ community.

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  Erica MomandKiddo: Here is my fabulously dumb SEO question:
  I have a few posts with non-optimized keywords. They have zero backlinks. If delete them an publish the same (or nearly the same) content fresh with a new permalink, is there anything bad that could happen?
  
  Thank you for your expertise!
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  Search Lab Marketing: If you delete the original and 301 the old urn to the new I see no problems with it.
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  Jim Munro: I am not an expert, Erica, but I would look it like this.
  
  Googlebot already knows your existing urls and they have been picking up steam as time goes on, optimised or not.
  
  A new url is like starting over brand new and deleting the old is like throwing earned value into the trash. ;
  
  I would leave the existing urls, and, if you have genuinely found a new way to tell the same story, then open up a new url and do it. ;
  
  Many will come along and talk about cannibalising keywords and duplicate content and they will most likely be right, but I think you should go ahead and do the new thing anyway and not worry about what has gone before. We might be overthinking it. :)
  
  I did not see Search Lab Marketing's post while typing this, but that might be a better idea than mine. ;
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  Erica MomandKiddo: Thank you for your input +Search Lab Marketing and +Jim Munro. The post doesn't really get any search traffic (probably zero) and I could easily materially change the text. I just don't want to be penalized for deleting posts - I have no idea if search engines penalize you for that sort of thing.
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  Saad Munir: If your previous posts are Indexed with Google and you uploaded them again with a new permalink, while deleting the previous. This will cause the 404 Errors and similarity of content. The best way to do is to upload the content on the new URL's and redirect the previous ones to the new URLs. ;
  But again doing it to a mass level might also have it's own impact.
  Read this post it will help you ;
  http://moz.com/blog/save-your-website-with-redirects
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  Jim Munro: I think that you can be confident that you will not be "penalised" for deleting posts, Erica. It is just that you are withdrawing that url from the race.
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  Erica MomandKiddo: Excellent, thank you.
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  G.S. Marjara: +Erica MomandKiddo to be more sure and safe you can request Google to deindex old urls till they do so 301 redirect is good option.
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  Joseph Paulino: If those really have zero backlinks and you're positive that no one else knows about the URLs to these posts, make sure you still do 301 redirects from each old post to the new version post URL.
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  Chandima Bandara: I agree with +Joseph Paulino ;If your URL is not popular or in other words promoted, then there should not be any panic. But making redirects is key since having "404 Not Found" pages are no good, if you want the visitors to keep coming back. ;
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  Joseph Paulino: +Chandima Bandara
   ;well said
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  Chandima Bandara: +Joseph Paulino ;Thank you.
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  Erica MomandKiddo: Thanks all, I'm setting up a 301. It's lovely to have advice from people who know their stuff.