Q: track iphone with serial number

Nope.

No. You can only track an iPhone if you set up Find My iPhone on the device and whoever has the iPhone has not disabled that service. If you did set up Find My iPhone, you may be able to locate the unit through iCloud.com.

Regards.

Well, Apple does not connect an iPhone to a network, cellular service providers do that (it is their network afterall, not Apple's).

And yes, if restored as new, anyone can use an iPhone as they wish.  If yours was stolen, you need to talk to the police about justice over it.

My son's iPhone was stolen a few months ago and had Find My iPhone installed. It didn't do any good. Even though he had a pass code on his phone, the thief was able to plug it into a computer and wipe it. Find My iPhone app will ONLY work if the phone is turned on and has NOT been wiped clean.

?? I never mentioned find my iPhone, and I am fully aware of how it works and what its limitations are.

Can iPhone be registered to iCloud using the serial number? My IPhone was stolen 2weeks ago,and was unprotected or registered to icluod, or find my iPhone or anything,,, can apple block it from their system, so the thief can't use it or access it at all?

No, Apple has nothing to do with lost or stolen devices.  Call your service provider and ask them about IMEI blocking (some do it, many do not, but it is up to carriers to restrict or block which devices access their networks).

It's weird that this many people are complaining about their Apple products stolen and yet the company will offer nothing to track it with the serial #. Do I smell a conspiracy here?

No other phone makers do this.

What other company, of any kind, track their device?

No more than Motorola, Samsung, Nokia, and LG are conspiring.  Cell phone manufacturers aren't in the law enforcement business. 

Can you sign up for icloud with the serial number only? I lost my iopd touch, and i didnt have any find my iphone or icloud stuff on it. Or can you track it with the serial number? I need an anwer bad. You look really qualified because of all your points. Thats why Im asking you random questions.

No, you sign up for iCloud using an AppleID from any iOS device or Apple computer - has nothing at all to do with a serial number of any of your devices.  Even if you could sign up, you need to have the iCloud account installed and active on the lost device BEFORE it went missing - you cannot make a device "findable" after it is already gone.

I agree. All this new technology should be tracked by serial number. Everything that has a GPS incorporated but the companies are better off not to offer this.