die-guest-blogging-dieYesterday, Matt Cutts foreshadowed the inevitable doomsday of guest blogging as a link-building tactic:
The decay and fall of guest blogging for SEO
At first, the post didn’t make clear that Matt was referring to doing guest blogging for SEO purposes, which in turn caused some mild frustration and confusion (both on Twitter and within the article’s comments). The title has since been amended and Matt has clarified that he simply wished to give people a heads up due to the practice of guest blogging (for links) becoming extremely spammy.
Let’s look at how this impacts both businesses and agencies.

Businesses

If you own a business—or even just a mildly successful blog, really—it’s likely you have at some point received seemingly innocent solicitations from content “do-gooders” wishing to provide 100% unique and engaging content tailored to your audience. Amazing!
The catch?
You agree to allow several links to their website within the article.
You could, of course, rel=”nofollow” these links, but chances are the content itself is usually pretty poor.
From Matt’s article:

I just want to highlight that a bunch of low-quality or spam sites have latched on to “guest blogging” as their link-building strategy, and we see a lot more spammy attempts to do guest blogging. Because of that, I’d recommend skepticism (or at least caution) when someone reaches out and offers you a guest blog article.

If you still wish to accept guest posts, I highly recommend that you only accept articles from people with whom you have some sort of an established relationship. When you host an article from another author, you are essentially vouching for the quality and authenticity of what that person has to say. Choose wisely.
Take a look at this still-relevant video from back in November 2012:

In short, if you continue to post low-quality content from an ever-increasing number of authors, you’re setting yourself up for trouble.
If, on the other hand, your blog has multiple authors and/or you accept only high-quality contributions, you have nothing to worry about.
For an example of guest blogging done right, see YouMoz. Not only is every piece of undeniable quality, they must meet strict guidelines.
One last piece of advice: if you accept guest posts, don’t label them as such. You can still include a guest author’s bio without needing to spell out that it’s a guest post. If it’s valuable to your readers, it shouldn’t matter from whom it came.
Quality always wins.

Agencies

For agencies or in-house SEOs writing high-quality articles as guest posts—and strategically sharing them in well-spaced intervals—you (again) have nothing to worry about.
If you want to be extra cautious, you can always remove links from your guest posts (or rel=”nofollow” them), but this is likely excessive if the sites on which you’re posting are of high quality and if the links aren’t stuffed with keyword-heavy anchor text.
Unless blatant, Google has no way to automatically determine between guest posts and other forms of content (e.g. pieces from regular contributors). The primary reason for Matt’s article was to caution businesses about falling victim to spammy links in guest-blog articles they may typically choose to accept and host on their sites.
As agencies and/or in-house SEOs, we (should) already know better. Unfortunately, in an effort to game the system, many people continue to search for easy/scalable methods of link building. That Matt noted a significant increase in the abuse of this particular tactic should serve as a reminder to anyone abusing this approach; it’s not going unnoticed.

Guest Blogging Benefits Beyond Links

Link-building efforts aside, guest blogging opens you up to a wide variety of new, bigger, varying audiences. It’s a great way to increase brand exposure, boost your influence and expand your reach.
Highly targeted referral traffic can be extremely beneficial, too.
If you’re pursuing guest-blogging opportunities for these reasons—and not in an effort to stockpile questionable links—it can remain an extremely effective tactic in your overall marketing strategy.