The 'Search for similar documents' and 'Semantic Web Creator' tools, as well as the 'Find similar documents' function now build upon the Yahoo Search API. Previously, the
Google Search API was used for all of these.
However, some time ago, Google has closed this API for new users, obviously in an attempt to win users over to their new
AJAX Search API. The API still works for old users but has become somewhat unreliable as of lately, which is why I decided to switch to the
Yahoo Search API instead.
The
Yahoo Search API is limited to 5,000 requests per IP per day, as opposed to the 1,000 queries allowed per day with the old
Google Search API.