OAuth is an open protocol that allows applications and websites to share sensitive data, without requiring you to release your password. Using OAuth, you can permit third-party applications to read from your Ohloh account without having to share your password.
Instead of handing out your Ohloh account password to a third-party application, you visit the Ohloh website directly and grant that application permission to access your Ohloh account. You can revoke this permission any time you change your mind.
In order to become Ohloh OAuth consumer, you'd need to get your key and secret from your API Keys page. Ohloh supports OAuth 1.0a. ohloh_oauth_sinatra.rb is a simple Sinatra based example using oauth gem that fetches authenticated user's account xml.
Although not affiliated with Ohloh, OmniAuth appears to have Ohloh strategy available here. This code is not supported, tested or verified by Ohloh.
OAuth is an optional, additional feature of the Ohloh API that can be used to integrate Ohloh users on your website using their authenticated identity. You can read public data from Ohloh at any time using only your application’s Ohloh API Key.