Nintendo has announced that it will end support for its online multiplayer service on the DS and Wii. Nintendo Wi-Fi Connection will shut down on May 20th, meaning that games will no longer work online; offline features, however, will continue to work. Wii apps like Hulu, YouTube, and the built-in browser will also remain unaffected, as will the online store. The announcement comes under a year after Nintendo said it would kill various built-in apps on the Wii.
Although Nintendo Wi-Fi Connection supported popular titles in series like Mario Kart and Super Smash Bros., the DS and Wii were never seen as a haven for online gaming, partly because they employed an inconvenient system of "friend codes" rather than Xbox Live-style profiles. Late last year Nintendo released a version of the Wii, called the Wii Mini, that removed internet connectivity altogether.
Nintendo of Japan made the Wi-Fi Connection announcement today; The Verge has contacted representatives to confirm that the news applies worldwide.
Update: Nintendo of America and Australia have also confirmed the news.