HTTP Get Rocks
Abstractions leak. Technorati's API returns well formed XML unless any excerpt contains an ampersand, it which case it doesn't. If this was buried under layers of XML-RPC or SOAP or content:encoding, this would be hard to find and even harder to deal with.
As it is, I can just cut and paste the URL into either Mozilla or IE, and I am told immediately what is wrong with the response. Given this data, I can switch from Mark Pilgrims's pyTechnorati to Phillip Pearson's and be back up and running in minutes...
Don't let the experts fool you. You won't find the real reason to use HTTP GET here. The real reason why you want to use HTTP GET is found here.
This being said, when you blow past any reasonable length of a URL or want to do more than simple information retrieval, it makes sense to introduce back in XML and HTTP POST. But my advice is to do so in this way instead of that way. That way you are better prepared the next time abstractions leak.