Dan's answer is technically correct in every way but I want to remind you *why* there's no direct way to "follow" somebody on the site. **When you follow people instead of topics, your votes start to become targeted.** It gives your friends an unfair advantage over others just because of *who* they are, not on the merits of their posts' quality.

I've covered this in more detail before: https://meta.askubuntu.com/questions/5267/guidelines-when-voting-for-friends 

If you are going to follow somebody via their RSS, I would suggest you either prevent yourself from voting, or at least make extra-sure that your votes are warranted, and that you're using the rest of the site normally too. If your account registers a lot of votes for one account, it will raise alarms and may even elicit the fabled *rusty spoon*.