Temporally Relevant claims that GBase, Google’s attempt at classifieds, is in practice nothing but a walled garden. The content is protected from other search engines by the code:

http://base.google.com/robots.txt:
User-agent: *
…
Disallow: /base

“Your content that you’ve entrusted to them to ‘host and make searchable online’ is sitting squarely inside of Google Fort, armed with locked doors for their competition by blocking the very thing that made them a success, the open web.”

The website seems to have a point. Since the post is currently sitting in tech.memeorandum we may well get a response from Google.