SEOmoz announced the launch of a new valuable tool named Open Site Explorer. I will not go over the features, every other blog did that.
The tool is extremely powerful, but it is not completely "open" or "free" as the name implies. Either way - the tool is impressive and for the most part, the SEO industry is very pleased with it. That includes Aaron Wall who called it slick, despite being Rand Fishkin's biggest critic.
Read more about the tool at the SEOmox blog and test it out at opensiteexplorer.org.
Forum discussion at Sphinn.