That latest Matt Cutts video about guest blogging sure lit up the blogosphere!
As everyone knows, one of the primary search signals is PageRank and PageRank is based on incoming links to your page, and one way to acquire incoming links is through guest blogging.
I've been planning to add my $.02 worth for the past few days, and although other have beat me to it, what they've said bears repeating.
Guest blogging is not dead.
Spamming guest blogging is dead.
What's the difference?
Guest blogging is real. You know them. They know you. There is a real connection in the real world.
Spam guest blogging is "high volume". Almost daily I receive a request to guest blog on one of my websites. For some reason a surprising number of these requests seem to come from people in the UK. They are companies who provide back link services to their clients.
How do they provide back links? By reaching out to website owners around the world and submitting guest blog requests.
So how can Google distinguish between guest blogging and spam guest blogging?
As I don't know any detail, I'll provide my preferred version of the high level answer, which is "statistical analysis".
What does that mean?
Never forget that the Google search engine is not "smart". It doesn't "think".
It compiles details about web pages and assesses patterns.
Some patterns are considered "natural", other patterns are considered "unnatural" or "spam". The details of this algorithm are not made public and even if they were I probably couldn't follow the math anyway.
The important point is:
If you think something is natural and organic, it probably is. If you want to guest post on Sally's interior decorator blog because you know Sally, you have something to add, and you can generate a back link to a relevant post on your website, do it.
If you think something is unnatural and not organic, don't do it!!!!!
Remember that Matt is the head of Google's Webspam Team, not their Search Algorithm team.
I believe this subtle distinction in title is important.
Any time you wish to do something to increase the ranking of your website, ask yourself "Does it feel like spam?". If it does, sooner or later Google will update the algorithm to negate it's effectiveness.