Connections are made automatically based on who you follow or who follows you on other sites. What this means is that you will automatically follow other coders that you follow on your linked accounts and vice versa.
Here is an example: Your friend Tom is already on coderbits and has linked to his GitHub account. You follow Tom on GitHub. When you link to your GitHub account, you will automatically follow Tom on coderbits. Tom may or may not follow you on coderbits depending on whether or not he follows you on GitHub.
The sites supported for connections are Bitbucket, Dribbble, Geeklist, GitHub, LinkedIn, and Twitter.
You can also control who you follow manually. Go to the coder's profile you want to follow or stop following and use the button on the upper right side. When unfollowing a coder it is important to understand that this turns off all future automatic following that may have occurred from linked accounts for that coder.