Dirurl - free backlink builder, Enter domain to get instant free backlinks. dirurl is a service that will automatically add your site to 113 different websites with google pagerank over 2 and alexa. Google pubsubhubbub hub - google app engine, Welcome to the google pubsubhubbub hub! this hub conforms to the pubsubhubbub 0.4 specification. in addition, this hub conforms to the pubsubhubbub 0.3 specification.