Twitter is a powerful infotention tool if you use it that way. Discovering experts and learning from them is key. I use Diigo and Delicious as hunting groungs for expertise, then follow the expert candidates I find in a particular field via Twitter lists. These step-by-step instructions can be useful to those who don't already use Twitter this way.
Sometimes you need to quickly immerse yourself in a new field. You might want to gain expertise or quickly gauge what the current issues are around a particular topic. One way of doing this is by creating a dedicated Twitter account to follow a topic. Below some instructions on how you could do this.
Setting up a Twitter account with the right settings