Okay I found what may be the biggest difference between Netamo and other manufacturers. Most other weather station manufacturers design their products to directly connect to WU. The station owner needs to go through the process of creating their WU account and station details setup, and then get their ID and password to upload direct.
But Netamo goes about it totally different. They don't have their customers directly deal with WU. Instead Netamo users only create Netamo accounts. I read the following in an Amazon review of Netamo hardware.
In the "Best case scenario" your data is meant to magically show up at Weather Underground after an unknown delay, and then you can email WU and ask them to associate the station with your account. The Netatmo forums show that this is hit or miss at best. It is complicated by many Netatmo users installing the temperature sensor in direct sunlight and generating bad data which must be filtered out.
Seems like Netamo designed their product with some setup simplicity for their customers. But that required special arrangements with WU.
Phew! I was worried about other manufacturers there for a moment. Sux for Netamo customers.