www.geotribes.com privides this facility, but it is not well implemented there. I have about 40 trackables, and as it gathers my data, I get 2-3 HTTP timeouts, have to hit refreash. eventually the data appears. Works great for normal trackables that are travelling, put personal ones, that you always keep on you, it does not seem to see.
I am sure PGC could do a better job that does not involve the http timeouts.