I have heard many experts state that the use of a CDN has no impact on SEO, but I am not convinced. Clearly speeding up a website WILL have a positive impact but my primary area of concern is with regard to PageRank.
My understanding of pagerank is that it is calculated on a per domain basis and that each sub-domain is considered a separate domain.
IF that is true - surely offloading static content from your primary site 'myexample,com' to a sub-domain at 'static.mydomain.com' ( which is CNAMED to the CDN) would REDUCE the pagerank of 'myexample.com' because the 'juice' from all that static content would accrue to the sub-domain and not the main site which is where you want it.
I am currently having to make a decision about using a CDN and balancing the many benefits against the potential loss of PR juice.
I would appreciate any insights or experiences with this.