This may be old news but I found this site:
http://www.marinetraffic.com/ais/default.aspx?centerx=30¢ery=25&zoom=2&level1=140 (http://www.marinetraffic.com/ais/default.aspx?centerx=30¢ery=25&zoom=2&level1=140)
When you can't cruise yourself you can always look at other people doing it and also see how heavy the traffic is in an area while planning next seasons voyage. Or just take a short break from work...
Interesting to see how, over time, more and more traffic comes online.