Yes, you can publish the same doc on many doc sharing sites but this is duplicate content for search engines.

If you have your own document and if its not copyrighted material yes you can publish it without any problem

The same content will work but instead of changing the whole ppt files (let's say you're uploading on slideshare, scribd etc), just change 1-2 slides and you're good to go.

Include the Youtube Video as well on slideshare for best results.

Hi, You can earn good amount of traffic by submitting documents to the document sharing sites. You can insert hyperlink the document as well.

A few of the websites that you mentioned are on our list of authority sites that rank quickly in Google (eg. slideshare). Rather than just putting a bunch of content out there and hoping that people will see it, you should identify the keywords with high value and low competition (we have a strategy for this) and then optimize the content that you publish on these authority sites for these keywords. Once you have done this, build links to the authority sites.

I guarantee that if you do this, you will get multiple 1st page rankings on Google.

However, don't just limit yourself to document sharing websites. There are so many authority sites out there that you can use the strategy with.

Below are a few of the best that we have identified through our research:

1. YouTube
2. Amazon (ebooks)
3. Askville.Amazon.com (Similar to Yahoo Answers)
4. Facebook Pages
5. Squidoo (Works well but have cracked down and have started banning accounts)
6. Meetup.com ($12/month) The group page ranks very easily
7. LinkedIn (The Company Profile Page)
8. Twitter Profile
9. Tumblr (May be able to pull in RSS feeds)
10. Myspace Account
11. Blogspot
12. BBB.org (This is an authority for Google+ Local Business Pages)
13. Dailymotion.com (Video site that is less strict than YouTube)
14. Metacafe.com (Video site that is less strict than YouTube)
15. Pinterest Profile (Rank Really Well)
16. Yahoo Answers
17. Itunes Stores
18. Google+ Accounts
19. EvenBrite.com (Similar to Meetup.com)
20. Craigslist.org (Can rank well for local listings. Downside is that they can be flagged and they expire. Good for short-term rankings)
21. Ireport.cnn.com (Can create an account as a reporter. Really easy to rank these pages)
22. Press Releases (These are possibly the best ParaSites, besides YouTube.)
23. Blog.co.uk (High authority site for the UK market)
24. Yelp.com (For Local Businesses)
25. sites.google.com (Another Google Property)
26. slideshare.net
27. Photobucket
28. Panaramio
29. Flickr
30. WordPress

It won't matter unless the content is your, you can submit it to as many doc sharing sites. It will generate some good traffic.