@saskwatch: This is just from my experience sending registered AirMail from Singapore. Tracking number will get updated about 24 hours (working days) from posting. Package will then processed. Upon leaving the country, there is no use tracking on Singapore Post website. Give it a few days / a week then check using the same tracking number on your country's postal sites (Deutsche Post perhaps). Now... here is the catch... the same tracking number may not work or will only appear on the website just the day the package gets delivered to you. I have tried this on Canada Postal Service and USPS website many times. Tracking should work but only the day of delivery is recorded.
Now for EMS, this has more elaborate tracking. Let say you have a package from China, tracking number will be usable on the website only 24 hours after item is posted and received on the post office side (apparently, dealers have already predefined form with tracking number that they can fill in but postage may not be necessarily on that day, very much like Electronic Shipping on USPS). So receiving tracking number (EMS) doesn't necessarily mean the post office has already gotten hold of your item.
Again, the same cycles applied... EMS China will update the site only until package leaving country (very rarely gotten the notice that it's delivered). You have to continue tracking on your country postal service website.