The Cynamite article uses (the German equivalents of) words like "official" and "confirmed", but we have our doubts-- stemming mainly from the fact that it was posted on December 1st of last year and nobody else has said anything about it since. We find it odd that Nintendo would reveal a new feature to only one magazine, over four months (or however long it may be before such an announcement occurs) before its official announcement in any region.
We also find it odd that this news would be delivered in Europe and nowhere else; Europe isn't exactly the first priority for video game companies, as any gamer living there has discovered. It seems more likely that this news would eventually come out of multiple Nintendo representatives in communication with multiple sources-- at least one per region. And we'd really expect this kind of big exclusive to come to a Japanese magazine like Famitsu.
Don't despair yet, small-free-game-segment fans. Just because this particular posting probably isn't an official announcement doesn't mean Nintendo won't eventually start offering demo downloads. They've got a nice Internet-capable console now, and they're delivering actual games over the Internet for the first time. Why wouldn't they throw some demos up on one of the Wii channels?