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Unless the load balancing is causing your system to 404 or 500 I cannot see any SEO impact. We did have to change the way we handled session state when we switched to load balancing to ensure state was valid on our shopping cart calls but that is more a developer issue than SEO. Most major hosts now tend to use VM, Cloud or other resource load balancing behind the scenes to keep their costs down without impact to SEO of their clients.

if you want to rank competitively in the US and AU then I strongly recommend local domains. In my experience, subfolders on a single domain are less effective then local domains. The above solution can work and you are at an advantage that your CA site is established and is the "parent" site. It is more work to maintain separate domains, but in my experience of managing .com sites, we have always faced a challenge because despite the target setting in WMT, Google still struggles to rank the UK site in the UK over the US site in many instances because it is on a .com and because there is a US version of the site.

The challenge is we are speaking in general terms. It would help if you shared a lot more specifics. Generally speaking, if the blog content was directly related to my domain, I would want the blog to be on the main domain. If I had corvettes.com and I wanted to add a blog discussing corvettes, I would choose something like corvettes.com/blog. If I had corvettes.com and I wanted to add a blog discussing cars in general, I may wish to separate the blog from my core site by using a subdomain. There will certainly be some relevant opportunities between the blog and the main site. If I wanted to create a blog to discuss unrelated matters, then I would pursue a different url altogether.

Please read this, from Google Webmasters Central: http://www.google.com/support/webmasters/bin/answer.py?answer=40349&query=cookies&topic=&type= Make your site easily accessible "Build your site with a logical link structure. Every page should be reachable from at least one static text link. Use a text browser, such as Lynx, to examine your site. Most spiders see your site much as Lynx would. If features such as JavaScript, cookies, session IDs, frames, DHTML, or Macromedia Flash keep you from seeing your entire site in a text browser, then spiders may have trouble crawling it. " Based on this, my initial thoughts are that Google will only crawl and index the default language version of the page. I would look to append something to the URL to differentiate the two language versions. I've subscribed to this thread because this is something I'm interested in too, I hope someone else with a little more experience can clarify this for us both, but in the mean time have a read of the above! I hope it helps Aaron