I'm spending three weeks on the road in the next month, so I've got three hand-picked guest bloggers taking over the mike on my site, for the duration. Emphasis on hand-picked, i.e. invited because they're interesting and I'm hoping my readers will enjoy what they've got to say. I get to take some time off, they get access to a new audience, and the audience get some new and thought-provoking material -- because from my PoV it's not about SEO, it's all about the quality of the content. (Hint: I'm a novelist, one of the guests is a film-maker, the other two are other novelists. We all pretty much live or die by the quality of our writing.)
The question I'm asking is, how do google's algorithmic processes figure out whether a post is a guest post? Are they doing style analysis on prose now? Or counting outbound links, or looking for anomalous keywords? Or is it just a matter of looking for spam-flavoured advertorial?
beambot, I agree with your comments and adjusted the title of my post and added on to the end of my post to give more context. Certainly not all guest blogging is bad (e.g. valid reasons for guest blogging include exposure, branding, audience, community, expert opinions, etc.). We just see a lot of spammers exploiting guest blogging and innocent site owners as an SEO tactic, so I wanted to make it clear that we reserve the right to take action where we see abuse.
It seems like all the legit reasons to link out have nothing to do with search rankings, so why risk Google's Ire?
More importantly, if No Follow becomes the default, wont that be a net negative for Google's index?
Did they agree to take the guest blogging stint to promote their careers / work generally (or just for fun)? Or did they do it for the purpose of increasing the page rank of whatever websites they happen to have an interest in?
If it was one of the former reasons, I don't think whatever changes are coming down the pike should be a big deal. Although I can't speak for google, I imagine that whatever algorithm they use will look for pervasive patterns. So assuming that this guest blogging stint is a rare or unique thing for these guys whatever changes are made will probably have no effect at all (i.e. the dofollow links will still "work"). The next most likely thing to happen is that the algorithm somehow figures out that they are guest posting and disregard the any backlinks. Finally, there's a possibility that there will be a slightly negative effect. If it does turn out to be the case there is a penalty, then in the future you can configure the CMS software to put nofollow on guest post links and then it will certainly be neutral.
Regardless, they will still all get the exposure that comes from getting their names out in front of your blog's regular audience.