http://www.warrenellis.com/?p=7831

looks like a interesting bit of video, and it seems like the reader range is a bit shorter then i expected (altho a bigger antenna could probably fix that).

btw, note the size of that circular tag, and that most of the circle is the antenna...

Strawberry RFID fields forever!

Very interesting clip there. Thank you for sharing it.

Argh! Accidental multipost!

Quite interesting, indeed.

Perhaps it can help end some of the RFID paranoia - it certainly demonstrates that pretty sizable RFID Tags (compared to the SR4 Paranoiatags) have pretty small readable volumes.

well its not fully transferable to SR as the SR rfid range is based on the SR signal rating table...

That's NFC, which means "Near Field Communication". It's a subpart of RFID with some specifications, including a range inferior to 10cm.
That doesn't mean there aren't RFID tags out there with a much longer range (up to 100m IIRC). Longer range (and bigger payload) implies bigger energy use so tags with long ranges or which need to send a lot of data are often battery assisted.

As for the size of tags and the amount of data you can store on it, I've got some circular NFC tags with a diameter of about 1cm (and not much thinner than a sticker). They can store up to 1kb, but there are probably 4k version out there. FeliCa (the ubiquitous Asian NFC Smartcard technology) can store up to 1Mb on a smartcard (the size of a regular credit card, maybe a bit thicker but not much). But most of the time, they'll just store an ID and the real data will be on a server somewhere so the storage size doesn't really matter.