If we have penguins on a SMP server eventually a kid seven years or under would start spamming
"ZOMFG BREAK TEH ICEBERGZ!!!!!!1"
I played Club Penguin when i was about that age 7 years ago, and even then i thought that was annoying
playing xbox all day pwning noobs that are lame killing elites with my awsome shotgun sniping down stalkers with my pulse riffle playing tf2 pwn with fire gonna light the enemy with my big bad lighter! [url=http://www.minecraftanonymous.com][/url
Penguins sounds cool, but what would be the use of them. If they drop eggs, they can be replaced with chickens.
Do they need a "use"? IMO penguins adding appropriate colour to a snowy biome is reason enough for them to exist. In fact, if they are almost exactly the same as chickens, then it makes them easy to code. All you need is a new model and some sounds and recycle the chicken code to use them.
But Chickens flutter and float around. Penguins are fat, so they aren't going to be floating.