PR 6:
http://www.aolanswers.com
http://www.chacha.com
http://www.allexperts.com
http://www.justanswer.com
PR 5:
http://www.answerbag.com
http://www.askmehelpdesk.com
http://www.askdeb.com
PR 4:
http://www.blurtit.com
http://www.theanswerbank.co.uk
http://able2know.org
Ebook And Document Sharing Sites
PR 9:
http://www.issuu.com
PR 8:
http://www.slideshare.net
http://www.scribd.com
http://www.docs.google.com
PR 7:
http://www.freeebooks.net
http://www.docstoc.com
http://www.calameo.com
http://www.box.net