pdf submission help

hey

I've never really been big into pdf submission. I understand its pretty much an under the sink link. But I am trying to diversify as much as I can. I have been looking at different pdf submission sites that I found in threads here after using the search bar and I noticed that alot sites host the documents in a way that makes them like images, meaning no text links. This is pretty much useless and a huge waste of time to submit to them.

My question is did they do something wrong to make their links not text links or even clickable? What are some of the websites that allow text based pdf submission?

http://www.scribd.com/
http://www.docstoc.com/
http://www.calameo.com
http://member.thinkfree.com/
http://divshare.com/
http://www.keepandshare.com/
http://www.edocr.com/
http://www.4shared.com/
http://docs.google.com/
http://www.wepapers.com/
http://www.box.net
http://www.gigasize.com/
http://www.glasscubes.com/
http://writer.zoho.com/home?serviceurl=/index.do
http://www.doxtop.com
http://www.gazhoo.com/
http://www.yudu.com/
http://www.slideshare.net/
http://www.persianupload.net/
http://www.slingfile.com/
http://www.midupload.com/
http://memoware.com/
http://kewlshare.com/
http://filefactory.com/
http://2shared.com/
http://uploading.com/
https://www.easy-share.com/
http://www.mirrorcreator.com/
http://www.ziddu.com/
http://www.zshare.net/
http://www.myplick.com
http://www.badongo.com /
http://www.host-a.net /
http://hotfile.com /
http://ifile.it/
http://issuu.com /
http://www.mediafire.com /
http://www.datafilehost.com /
http://www.sendspace.com/
http://www.wikiupload.com/
http://depositfiles.com/
http://www.megafileupload.com/
http://uploaded.to/
http://www.gamefront.com/
http://uploadingit.com/
http://turboupload.com/
http://www.wupload.in
http://www.yourfilelink.com/
http://www.bigupload.com/
http://www.files.com/
http://www.speedyshare.com/

The PDFs have their own urls and are indexed in Google when they are discovered. You can exclude the sites that don't work this way. By the way, you don't need many pdf backlinks.

Google can read the pdf on those sites, and can crawl them for your link, even if they have an embed or whatever that makes the link not clickable. So you still get a backlink, although those sites may not give you as much traffic.