Guest blogging has become common practise and can also be an opportunity to achieve back links. More importantly, it is an avenue for a writer (whether well known or not) to build a rapport with the Blog audience and offer useful and informative information. With social media, your post can also reach audiences beyond the Blog audience.
Where it becomes low quality is when the post is solely written for the purpose of obtaining link(s) and offers no value.
Matt Cutts from Google has recently answered a question about guest blogging (video below) and I quote the following:
- It is a worthwhile exercise especially from high quality writers
- It can also be a great opportunity for a writer who isn’t as well known but produces high quality work
- Where it is not good is when the practise of guest blogging is taken to extremes, for example the same blog post is distributed multiple times or spinning the blog and distributing to multiple sources. Once it becomes a mass production kind of activity where low quality posts are produced for the sole purpose of obtaining links, these are the types of links Google won’t count.
As Matt has mentioned, there is a case for high quality posts that are well written and offer value rather than those posts which are of low quality and offer the bare minimum just to get by.
Bill Vasiliadis
Bill Vasiliadis: Australian SEO & Digital Marketing Consultant 
Cool. Then my website is open for guest authors to post unique posts to get free backlinks 😉