Sup Duncan, the 64 byte dry inlays can store any data you see fit. URL, text, phone number, etc. Each character in these types equates to 1 byte so it all depends on how many characters you’re trying to store. Also keep in mind that there is some “header overhead” related to NDEF formatting (what is used to store characters on NFC tags). What this means is that effectively you only have about 48 bytes out of the 64 bytes that you can use. With URL shortner services like bit.ly and goo.gl it’s usually not a problem storing any length URL you have.
hope this helps.
