Why does my spawn point change on my SMP server every time I respawn?

It seems that my spawn point on my SMP server keeps changing every time I kill myself and respawn. The spawn points all seem to be very close to each other (within sight) but still not at the same location.

I have no mods installed. I just used what Mojang distributed.

Why do I keep spawning at a diiferent point everytime I respawn?

Solution 1:

There is a "spawn point", but you actually spawn anywhere within about 30 blocks of it. Try deopping and trying to damage the environment, wherever you can't touch is part of spawn. The "spawn point" will be in dead center.

You can use this to build a "spawn area".

Solution 2:

There is not so much a spawn point as there is a spawn area.

In multiplayer, players will spawn, by default, anywhere within a 20x20 area centered at the spawn point. An individual player can change their spawn point by merely lying in a bed -- they do not have to go to sleep (which can only happen if all players sleep at the same time).