I didn't get that from Rand's blog although I have read it. I got my figures through testing with some junk domains (I experimented with around 25 domains - .net, .com and .infos) to see of they get sandboxed when pushing X amount of links to it or by doing certain things and those were the results which I found albeit it's a small sample size.

Regarding the second part, it's very easy to beat the approval system on many blogging softwares - Wordpress for instance is extremely easy to do.

And regardless if you agree with me or not, blog commenting is a Grey Hat SEO technique. I also said that the effects for doing a few links is minimal in terms of negatively affecting a sites SEO rankings which I agree with you on, I am just disagreeing with you over the fact that this should be a startup's SEO strategy