phranque - 2:04 am on Jul 16, 2013 (gmt 0)
welcome to WebmasterWorld, dn00bmaster!
1) according to Google's Webmaster Tools Help:
Cloaking refers to the practice of presenting different content or URLs to human users and search engines.
2) this is often niche-dependent but i doubt there are many niches where 50% exact keyword anchor text looks like a natural link profile.
this thread may give you some useful guidelines - EMD Branding Strategy:
3) things haven't changed much regarding keyword density since this discussion.
Keyword Density - Keyword Discussion forum: