The package seems to be helpful, and it's great to see that now we're having 2 anti-spam packages.
What I didn't like though:
- Class variables are not documented. They have docblocks, but you don't tell us what they actually /mean/.
- The response object is very unclear. You don't describe it's structure and just link to some api page.
- $response = new stdClass(); does not help anyone and is also wrong, since parseResponse() says it returns an array. You should return a response object with helper methods like getType(), isSearchEngine(), isSpammer() and such.