Can a mailed letter be traced?

Related questions

1. How do I track my xpresspost?
2. What is Canada Post Xpresspost?
3. How long does it take a package to clear customs in Canada?
4. Is tracking number same as reference number?
5. How long does it take for first class post to arrive?
6. Can you track where the USPS truck is?
7. What is FedEx TNT?
8. Can I track my package without tracking number?
9. What is Smle shipping?
10. Does proof of posting have a tracking number?

Tags

1. #class
2. #method
3. #label
4. #certified
5. #priority
6. #using
7. #insured
8. #number
9. #without
10. #impossible
11. #first
12. #traced
13. #express
14. #letters
15. #letter
16. #assigned
17. #unique
18. #cannot
19. #print
20. #tracking
21. #cases
22. #registered