Matt Cutts: What is Google doing to combat the effects of comment spam?
Topic: What is Google doing to combat the effects of comment spam? – Quick Answer: Nofollow links
Matt Cutts: Is it worth spending time on creating tags and categories?
Topic: Is it worth spending time on creating tags and categories? – Quick Answer: In general, Google figure out what your post is about, so don’t worry too much about it
Matt Cutts: How many search algorithm changes were made in 2009?
Topic: How many search algorithm changes were made in 2009? – Quick Answer: 350-400
Matt Cutts: Will having a site available on both IPv4 and IPv6 cause a duplicate content issue?
Topic: Will having a site available on both IPv4 and IPv6 cause a duplicate content issue? – Quick Answer: No
Matt Cutts: Should large corporations use rel=canonical on every page?
Topic: Should large corporations use rel=canonical on every page? – Quick Answer: They can, but fix the structure first. Be careful with it