Sierra Community Forums have news that Sierra is planning on closing multiplayer servers for 21 different games as of November 1 of this year. There's no indication if this has to do with the Activision Blizzard merger or if this is normal end-of-life for supporting these games, but there are some noteworthy titles on this list (thanks Eurogamer). Here's the list of server on death row:

1. Alien vs Predator 2
2. Arcanum
3. Caesar IV
4. Dark Reign 2
5. Emperor: Rise of the Middle Kingdom
6. Empire Earth
7. Empire Earth 2
8. Empire Earth: Age of Conquest
9. Ground Control
10. Ground Control2
11. Homeworld
12. Homeworld: Cataclysm
13. Nolf2
14. Red Baron
15. Sanity
16. Star Trek: Armada
17. SWAT3: EE
18. SWAT3: GOTY
19. The Incredible Machine
20. Tribes2
21. Vampire