At the SMX Sydney conference this week, a conversation between Fishkin and Darren Rowse about Twitter's influence on search brought to light several SEO issues around earning links, or PageRank, for Web site content. Fishkin notes it "could be 12-24 hours between when content is first 'tweeted' vs. when it earns its first external link." If this trend among bloggers continues, "search engines will need to start relying on Twitter's tweet graph, particularly for 'new' information and content."