For instance if someone had my MAC address would they have my name and address location or would they just have the name of my device. Also could they track me down by having the MAC address or would they need to go to court and sobpeana this information.
For legitimate devices the MAC address is directly tied to the hardware and often burned into "rom" on the network card itself (but sometimes it's not actually read only). To prevent collisions each vendor has a set of prefixes they're allowed to use, and it's up to them how they use them and how they uniquely generate the rest of the MAC
Therefore you can reliably get
- The hardware vendor from the prefix
- Often the approximate generation of the device based on which prefix is used
- Sometimes the exact model of network card used since most vendors use a predictable process to generate part of the address
- Very rarely some other piece of information the vendor used to generate it when the card was made which usually isn't very useful
You can get the vendor from Wireshark using their tool
But a hacker can, through a variety of ways, falsify a mac address to pretend to be pretty much anything. Even mimicking another device on the network (though if they do this without knocking the other device out you end up with each device receiving only some of the packets which is both useless to the hacker and alerts the admins that something's probably wrong)
As for tracking, the MAC can reliably (though not uncontestably) tie traffic to a single "machine". This information is overwritten each time traffic passes through a "layer 3" device (like your router). Normally this means that at most your router's mac address could be seen by another machine (and sometimes not even then, depending how the ISPs route their traffic).
Therefore the 3 biggest things to keep in mind if someone hostile got your mac address are
- If it's for your router and the hostile party is a hacker it could leak the approximate model and generation which is the first step to deciding which vulnerabilities to try and attack
- If it's for your router and the hostile party is a website or service, it might be able to log that and track sessions over time across multiple IP addresses (if your IP changes like how DSL does)
- If it's for your local computer or device (say from a software or browser leak), It can be used to uniquely track your computer across multiple sessions regardless of other anonymizing techniques, but it doesn't track YOU as a person. Also you can rotate your MAC using software if you're concerned about this, but that only helps if you remember to do so
Also there's other information that can track you besides just your mac address. For an interesting demonstration check out DoILeak.com
Edit: Floating some links that fell below the fold for people who might be interested in other tracking techniques