Well, what appears is that an HTTP request gets executed and is actually successful but no content is returned that we can decode via HTTP::Response::decoded_content or HTTP::Response::content, it is very hard for me to find out but the behavior seems universal regardless of the website I am querying, so maybe Google has stopped entertaining automated access via code for security probably, just a guess ..
my $pr = WWW::Google::PageRank->new;
my @context = $pr->get("http://www.perlmonks.org");
print $context->status_line, "<<<<\n"; #The request is carried out!
print $context->content,"\n"; #No result is returned
print $context->decoded_content,"\n"; #No result either