My comment was mainly referring to the first 500-1000 links of a website & avoiding being sandboxed etc due to significant changes with Penguin & Panda.
If a startup wants to link back then they should only do it if they aren't putting the keyword they want to rank for as their "name" which receives the link. However, this is still a Grey Hat SEO technique & whilst the risk reduces after the first 500-1000 links, it is much greater in those first core set of links & can easily see a website sandboxed.
As for the 500-1000 links thing, I assume you got that number from one of Rand's posts (http://moz.com/rand/the-first-500-links/).
First, those numbers and guidelines are entirely anecdotal. Yes, there is a "honeymoon" phase with new domains, but that's entirely unpredictable and there's no hard limit of links before you're in the clear (or in the danger zone for that matter).
Second, if a comment is put into moderation, and then must be approved by the blog owner, how is that anything but authentically earned? The blogger can approve or disprove your comment at her discretion, you're not exploiting any systems or anything.
I simply can't ever agree with someone who says that leaving a blog comment with your url in the website field makes you a Gray Hat SEO. If that were the case, there would be tens of thousands of mommy bloggers yelling at Google for banning their sites.
It's natural engagement with the community, with backlinks as a nice little perk.
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
https://twitter.com/iamdchuk/status/240989741246455810
Regardless of our disagreement here, thanks for the discussion!
Penguin and Panda were introduced to combat blatant spamming practices, both with link building and content based spamming. Manually commenting with thoughtful replies is just being a good community member, getting a link back to your root domain is a nice little token for your efforts, and I would love to see a single case study of someone employing the strategy outlined in my post (at the volume I suggest) getting slapped by Google.