| Sony product EMK-T01 is the Sony eMarker. Attaching to your keys, the eMarker is basically a USB interfaced hardware-implemented timestamp device. If you hear a song on your radio that you like, and you want to remember to go home and download the song, buy the CD, or just find out what the song is and by whom, you hit the button on the eMarker. A quick two toned chirp later, the eMarker has timestamped when you hit the button. Screw up? Hit the cancel button on the back of the unit.
When you go home, plug the eMarker into the USB cradle that it came with. eMarker will go to the website, upload your timestamps (which you can choose to save, delete, etc), and tell you what songs were playing at that time. You can listen to a sample (to make sure its the right song), find out about the artist, find out what album its on, etc.
How it works is every radio station HAS to make note of what songs were played and when, so the artist gets their royalties and stuff like that. Well, eMarker interfaces with this database and finds out what was on the air when you hit the button.
When you sign up, it says "These are the radio stations that we cover in your area" and you choose your favorite 3 (they continually add more stations). When you interface with the unit, you tell it what station you were listening to (or just guess amongst them) until you find the song you want that was on then.
They plan on doing more in the future with the unit, such as being able to eMark music videos on TV, and commercials
Requirements:
Using eMarker is free (they probably just harvest your listening preferences to sell to marketting firms and all). You just pay for the hardware, which costs about $20.
Only problems I've run into are that as of now, they dont cover classical or Jazz stations. Not a real problem for me, but it may be for some others. Most importantly:
CHECK YOUR COVERAGE AREA BEFORE PURCHASING AN EMARKER
While they cover over 1250 stations (as of 01-29-01), theres a chance your favorite station isn't on it. They're adding them, but it may take a while. Right now, the only stations that my emarker will cover in Poughkeepsie are some ones based in NYC, and somehow I doubt they play much music on WINS am 1010 (All news, all the time.) So do yourself a favor and check your coverage area before you buy one of these. )
You can find out more information at
http://www.eMarker.com/
Note: I'm rather happy with it. Sure its useless to me right now until they add my stations (WRRV 96.9, WPDH 101.5), but until then I'm getting my kicks by explaining to people what the unit is and how it works. (HEY! I've gotta put SOMETHING in all these pockets on my cargo pants | 
