I saw that they now had spidertracks capability a few weeks ago when I was registering on Lockheed's flight planning web site. While the spidertracks is cool, it's probably more than most private pilots want to spend. For the last couple of years I have made a shortened URL that redirects to my Spot page, then I put "live tracking link:
http://www.mytrackinglink.com/... in the flight plan comments field.
The ONE time I forgot to close my flightplan in a timely manner, I called in as soon as I remembered and found they had already closed my flightplan after using my Spot link to determine I had reached the airport. I was relieved my screwup had not forced a lot of people to go to work or be worried. Sort of a poor man's spidertrack.
BTW, Spot has a $50 rebate going on now for people that already have older Spots to upgrade to the Gen3. I upgraded from the original spot to the Gen3 and the battery life is awesome due to the motion sensor that elimitates repeated duplicate tracking transmissions from the same location... and the 5-minute tracking interval (down to 2.5 minutes if you want to pay extra) would really cut down the search area.