Lumberjack is tagged as “an access log for your blog.” From the website:

“Businesses use programs like Webalizer, Analog and WebTrends for traffic analysis, to guage the effectiveness of marketing programs, to tell them how people got to their site (i.e., referrer tracking), what they do when they’re there, what OS and browser they use, and so on. These hard-core traffic analysis tools require webserver access logs, and these logs are generally not available to bloggers unless they run their own webserver. This service solves this problem by creating access logs formatted identically to those found of webservers for weblogs.”