Was reading this article and thought of it on SIN's...
Its not official if its not on Facebook

So you'll have your relationship data, linked to your significant other(s?). So if you have coffee with the same person too many times, you're likely to be logged as in some type of relationship. After 3.. days (2070 works fast), you start getting spam about buying a ring for your significant other, or otherwise taking part in a corp sponsored binding contract between you and your other.

Besides the information to identify you, what else will end up being logged on your SIN?

Also going to add that this goes to show that outside of the runners, the public is going to be more than helpful in providing all their personal information. Even if you don't ask for it, everyone thinks that the world deserves to know everything about them.

The runners then run into the problem, of providing enough information so that they don't look like they are hiding something. But not providing enough information to get themselves caught easily. Or providing fake information... But what happens when someone tries to follow the link of your significant other, and finds out there isn't a person there, or the other person isn't listed as being with you. Nosy people...

Well SINs are what shadow runners use to look legit. They deal with anything you want to publicly purchase and can help you get into areas by showing that you are in fact a'ok. If you get on a bus or want to purchase a box of Soy'n Munch you need to use a SIN. If you get scanned or pass by a road block they will ask for your SIN. The way our game runs is that any SIN higher then rating 4 has to use the real biometrics of your character, or else it just doesn't cut the mustard (in that respect it makes SINners only get SINs up to rating 4.) Having a fake SIN fake license go basically hand in hand. "Yes officer as you can clearly see I have a permit for transporting a shipment of awakened drugs and that I am an independent shipping consultant by the name of Fred Spangler"... instead of having to run for it you actually have a good explanation at every checkpoint why you carry some of your hardware. Also I feel if you buy things with your SIN instead of looking in the shadows for scrubbed gear it is actually a lot cheaper and faster to get the item you want. You could spend forever to get that pistol you always wanted or just walk into a weapons mart and buy one off the rack. Although every rose has its thorn as all of what you buy with your SIN can be tracked.

Remember the rating of a SIN probably says most of what people need to know, and after enough time of snooping anyone should be able to find out if a SIN is fake or not no matter what the rating. Most people though will just give a faint glance at the database to see if your legit and then forget about you. I mean how many people check the back of credit or atm cards? I ask for ID when the back says "See ID," or does not have a signature. Generally I get the response of "You know I use this card all the time and you are like the third person who has asked for my ID." Why? Because nobody cares to look at the back of the card.

That points out that there is a weird 'limiter' on equipment in that you have no real rules for purchasing legally... assuming you have a license or don't need one (some items have a very high availability but no real restriction... if all the rules are followed it can take days or weeks to buy it in the shadows, but someone with a SIN (fake or otherwise), in theory, could simply walk/wireless a vendor and have it in minutes.

I'd say most likely you are correct. If you have a SIN and the item doesn't have a R or F behind it you could get it delivered right to your doorstep. Provided you want people to know you have it, and the serial number registered to you (or your fake SIN at least). The same thing would also probably apply to a R item if you had an appropriate fake license for it.

What's the deal with the signature anyway? That isn't security at all. First off, it's trivially easy to forge anyone's signature after a few practice attempts. Secondly, they don't look at your signature when you do sign something (try writing "Darth Vader" or "Dick Cheney" or "The woman with me is not my date, she is holding my family hostage, please call the police" instead of your signature. Actually don't do the last one, it's just awful). Point is they accept it, and if they didn't, you could get free stuff by paying with your credit card, signing wrong, and later claiming it wasn't you. Obviously that doesn't work. So your card is more secure if you don't sign it, because then retail dudes will ask for ID, and it's slightly more effort to print out a plastic card with your picture on it than it is to practice signing someone else's name a dozen times.

Sorry for the rant; I tried to pay for something with cash this morning and they wouldn't accept it.

What were you trying to buy? Because that's not legal. It is actually illegal for them to refuse your cash unless it's foreign currency.

Two things:
1) Someplaces, like the Post Office in the U.S. will not accept a credit card that doesn't have a signature, even if it says See ID.
2) Depending on how you sign and the disposition of theperson, they may not accept the card. For example, a few years ago, I delivered a pizza to someone who signed the credit card slip with his name and "Repuke-licans Suck". Well, me being the right wing Republican I am, looked on the back of the card and didn't see that line. I refused to accept it.

1) Hm. The signature doesn't make anything more secure, but some people won't accept an unsigned card. Lame.

2) I hope you're not saying that you sacrificed getting a tip rather than accept an insult to your ideology.

I was paying my rent at a property management company. The funny thing is, they had required cash when they were collecting the fee to run my credit history (which is also a total scam -- it's a crooked game, but it's the only game in town). I recognize that it's illegal to not accept cash but I wasn't about to debate it with the receptionist, because I had things to do with my life.