At the moment as part of my link building strategy for my main website I have about external 20 blogs (on two different hosting sites)and each blog provides content for a specific product and provide links to the main site.
My plan is to now move all the content from those external blogs into the main sites blog (to increase traffic and authority?).
Originally I was going to export content and put 301 redirects from the blogs to the main site.
Now I am thinking to set a canonical version on the main site and leave the blogs running (so I don't lose links - as they rank in SERPs for some of my keywords)..
What do you guys think would be the best strategy?
jessinspire, you've inspired a deafening silence. Welcome to WebmasterWorld. Tell me you're not pulling our leg.
Everything about your approach is going to be completely obvious to Google, ridiculously so, and it will be seen as crudely manipulative, and it will backfire big time.
Assuming that the main domain is one that you want to keep for longer than a few weeks, I'd forget the whole "strategy", dump the 20 feeder blogs, change your SEO reading habits, and focus on learning how to build a good site that is genuinely useful to users and can attract links on its own.
With the current setup, you're damned if you do and damned if you don't. I'm not sure which Google would dislike more... the redirection of previously promoted domains to a common domain, or the use of 20 commonly-hosted blogs as feeder sites.
If you want to do blackhat and to burn domains, that is your choice, but learn the basics of spam detection, so you're not wasting money on raw materials, get at least 18 more servers, and start over. These domains are already guilty by association. I doubt that you'll get much encouragement here.