Looking for your last one, tried to find in a couple of tagstreams, but there are 3 possible tagstream views...
1. HOT - this is the default view, so if it doesn't make it to "hot", it won't show
Found it in #freeebook under "all", in the others, I'm not scrolling that far.
Twitter may be prioritizing or despamming based on text versus link, so too little or generic text and a link may be treated as linkspam. If the link is killed by the #, then it's treated as a post with no link.