There's nothing wrong in guest bloggers to contributing to a site. I've published guests blogs on Landscape Juice on numerous occasions.
Often the person writing the content brings a new dynamic and writing style that is different to the blog owner's style.
What I'm referring to is guest blogs which are placed (and often paid for) by link builders. It's a practice that Google is keen to discourage and, in some cases, penalise.
If you are a blogger I'm sure you've had an email saying something like this?
"Hi, I've been researching the best garden blogs on the net and came across yours. Wow, I find it so entertaining, you are obviously such an expert in your field....kudos"
Then the author of the email leads into the sales spiel.
"I'd love to write something entertaining for your readers...in fact I'd find it an honour...in fact I'd be willing to pay [then the sucker punch] as long as you add a link to the article and mention my site".
Other approaches might be less subtle and straight to the point.
I had a request recently which was very direct [since deleted]. It went something like this:
"I've got one of the simplest advertising requests you'll ever get. I'd like to place our link on this page [page link to one of my articles] on your site...how little will it cost me?"
My answer was no, and it will cost you nothing.
Recently, something seems to have stirred the content bloggers, SEO experts and link builders and their emails are coming in with increasing regularity to Landscape Juice HQ.
For me it's part of the game, fielding these enquiries. With so much content on both Landscape Juice sites there's bound to be an attraction.
However I'm noticing a trend on other Google+ and personal/work blogs of articles that are clearly written by professional content builders, linking out to rather dubious pages that don't really reflect the content of the publishing site.
There are signs that these blogs have been placed just to gain link juice. They may or may not have been paid-for placements.
It's easy to be flattered by the attention and give in to the enquirer. These enquirers can be persistent too.
Recently I saw a rather sustained Twitter campaign by a landscaping company promoting a guest article on their blog. The content was actually relevant to the landscape industry but it looked worryingly like part of a link-building campaign.
There is a recent incident that all blog and site owners should be made aware of and should serve as a warning to others.
Google has recently penalised Interflora for unnatural link building which violated the search engine giant's terms.
Just before Velentine's Day, Interflora placed articles with regional newspapers and various bloggers hoping to get back-links to its website. Bloggers were sent free flowers as a reward.
Interflora were removed from search engine results pages for keywords relating to flowers as well as being demoted for their own brand name.
Punishments didn't stop there however. Sites who appeared to collude with Interflora by hosting the Interflora back-links had their page rank slashed.
So if you contacted and asked to publish an article, either decline of add a NoFollow attribute to avoid a potential penalty.