When you link your accounts such as GitHub and Stack Overflow we aggregate all that information to identify your skills. Most of the data we use comes from those sites such as the Language API call for repositories on GitHub or the Tags API call on Stack Overflow. In some cases the information they provide is may represent what they think you know but may not be correct.
For example, on Stack Overflow you may answer a question about Ruby but the original question was tagged as Ruby and Ruby on Rails. You may not know Ruby on Rails but that skill will show up on your coderbits profile.
To address cases like this, we have provided a way for you to hide skills from your profile. You can find this in the Skills section in the profile builder.