I started using MyBlogLog the other day because I saw it being used on a site I visited.  It's basically a statistics tracking site that can be easily integrated into an existing site with a javascript include.  Its most important feature is its ability to track outgoing links, which is something I've been thinking about for a while.  It also has the option to show which outgoing link was clicked and how many times it was clicked during the current day (called ClickTagging).  Its main downside is that it keeps trying to get you to sign up for a Pro account, which costs $3/month or $25/year (not a bad price, but I don't pay for anything).  The site is kinda painfully ugly, but the service is really simple and usable.  I'm a fan (for now). 

Update (2006-06-30 4:55pm):  I'm not a fan of waiting for another service to load when trying to access my site.  So long, MyBlogLog. 

#technology