In March I wrote a post named Google On Content Delivery Networks & Search Rankings. The answer was yes, but it depends on how you set it up.
An undisclosed CDN company came into the Google Webmaster Help forums asking Google additional questions on how they handle CDNs. His concern was two fold:
- Sites might seem to be hosted on multiple IPs
- Many many sites use the same small set of IPs
Google's Pierre Far responded to the question saying:
We generally do not treat sites hosted on CDNs any differently, and the answer you both of your questions is that it's generally not a problem.
A couple of things webmasters need to be mindful of:
1. If webmasters set up the CDN to be multiple hostnames that serve the same exact content (i.e. they create a duplicate content issue), we advise them to implement rel="canonical" or another canonicalization technique. I've referenced some Help Center articles for you about the topic.
2. One of the signals we use to geotarget websites is the IP address, which is more likely to change when using a CDN. If the website is using a generic TLD domain name (e.g. a .com), our algorithms may associate the website with a geographic region incorrectly based on the IP address. The solution to such a situation is to set the correct geotargeting using Webmaster Tools. I've referenced a Help Center article about this topic too.
The CDN Company asked Google about the concern of dynamic IPs and how they can get special classification for their IPs so Google knows what is going on. They, the CDN company, implied that Google has special treatment for large CDNs such as Akamai and they want on that list.
Personally, I don't think CDNs have to worry about their IPs dynamically changing for domains. I think as long as the IPs are within the same country region the sites and domains and content on them will be fine.
Forum discussion at Google Webmaster Help.