What's the alternative? I actually thought databases were the cutting edge. Or maybe I've been out of the loop.
http://www.h4labs.com/dev/ios/swift.html
I'd like to add more features but I don't want to reinvent everything. Anyway, Go and App Engine handle the load well and so far it has been free.
You will likely run out of the free tier and into significant spending during the spike pretty soon.
If you ran a highly interactive page that required a lot of non-trivial server-side processing, I'd understand.
But blogs serve the same static content to almost every request. I don't see why burning a whole lot of CPU and IO on it by running python/php/ruby and hitting a database many times is worth it. Serving a set of static files automatically generated by a blog engine (like Jekyll) seems much more reasonable to me.
Regarding comments: Disqus or something like that could help. Or you could turn the comments off during a spike: seeing the content without comments is a much better user experience than seeing a 500 Server Error page.