The effectiveness of using specific proxy servers depends upon which end of the the internet connection has had the block placed upon it.
For example, someone might be at work but wanting to access eBay. They know that they can't do so directly because their employer's IT department has added eBay to a list of blocked sites. To get round this, they can route their internet traffic via any proxy server, as long as that proxy isn't also on the employer's blocked list.
In that situation, the block is put on at the user's end of the system. However, when you access the Moviefone site, their server looks at your IP address and spots that you're in the UK. Because Moviefone doesn't have the overseas rights for the trailers you want to see, it will block your access. So, in this case, the block is put on at the remote end of the system. You can only access the trailers via a proxy based in the USA, which would fool Moviefone's server into thinking that the request was a domestic one. (I've no idea where the Proogly server is based, but it's probably somewhere like Russia. Proogly has no connection with Google). Further, you'd also have to find a proxy server, in the USA, that the Moviefone IT staff don't know about. (As soon as they spot that traffic is arriving via a proxy, they're legally obliged to block access from that server in order to prevent possible breaches of intellectual property rights).
Chris