Ken “I’m crazy MOO man” Fox got a chance to play with the Yahoo! Search Web Services last night. He brings up a very good point about how easy it is to get started. Even without using one of the provided SDKs, the REST model used by Yahoo! makes it dead simple to use the service. If you can request a URL and parse XML, you can use the service.
Contrast this with the Google search web services. You either have to know how to POST and process SOAP envelopes or you have to pull in an entire SOAP framework. The Google service was cool when it came out because it was new. Stacked alongside the new Yahoo! offering, it pales in comparison.
Of course, the real indication of who’s service is better will be determined by the applications that come out.