BuilderBot
Builder Bot is an automation bot released on the Minecraft forums in July of 2010. Builder Bot is an example of the most common Minecraft bot, and its primary function is to draw 2D and 3D cuboids. However, Builder Bot can also be used to draw lines, copy 2D and 3D sections of the map, "sponge" an area, or erase blocks of a certain type from an area. Builder Bot is a primary example of the types of Minecraft modifications used for griefing, and server admins should be aware of the potential harmful uses of the bot before allowing it on their server.
MineBot
MineBot is a custom bot built by Custom Bots in Visual Basic. MineBot is primarily used for building 3D structures quickly, like a box or a 3D picture. The video demonstration shows MineBot building a small room with a glass skylight and a multicolor 3D image in the sky. The bot also enables chatting in different colors.
Project Miner Bot
At time of publication, Miner Bot is a yet to be released bot for Minecraft the allegedly tunnels and mines automatically without any supervision. According to a video posted by the designers, Miner Bot will automatically tunnel at 45-degree angles collecting valuable resources that can be used for crafting. The video states that Miner Bot will plug up holes leading to caverns with cobblestones so as to avoid run ins with mobs and lava and to mark the caverns for easy identification when players are exploring the mines themselves. According to the Project Miner Bot homepage, only 200 copies of Miner Bot will be sold for a price ranging from $5.99 to $19.95, depending on when you purchase. However, there is very little evidence to suggest that Project Miner Bot is real, or that a legitimate end project will be delivered. If you watch the video on the homepage closely, you will notice that it only shows a loop of modified Minecraft game play.
Griefing
Griefing is a term used in Minecraft to refer to actions specifically aimed at ruining the game experience for other players, and bots are often used to facilitate this. Examples of griefing are using bots for random destruction of the map, obstruction, construction, fires, explosions, and in more extreme cases service disruption attacks, much like spamming or denial of service attacks. Minecraft server administrators should be fully aware of the griefing potential of bots before allowing them on their servers.