When you join Account Analysis by Luca, you sign up through the OAuth-Process of Twitter. The information I store on the server are your Twitter ID, your Twitter screenname, your Twitter language setting, your OAuth Token and Secret, the URL to your Twitter profile image, when you first signed up with Account Analysis by Luca and when you last logged in through Twitter. This information is needed for the service to work. The OAuth Token and Secret are used to request the data needed for analysis from Twitter.
Your Twitter OAuth Token and Secret are used to request Tweets and other information through the Twitter API. They are never shared with others. Adsense collects data to show you ads. Google Analytics data is anonymized and used to understand how the service is used and how to improve it.
I store only the minimum of information that is needed to provide this service. The most important information are your OAuth Token and Secret. I have taken steps to ensure my database is secure. If there ever is a breach, I will try to inform all users. You can revoke the OAuth Token and Secret from your Twitter settings at any time. Because the Token and Secret only offer the ability to read Tweets and other information from Twitter, an attacker could not take over your account or read direct messages.
Account Analysis by Luca stores a cookie on your computer to track you while you are on the site. The information in this cookie is a string of characters that is meaningless to everyone and everything except our server. No personal information is stored in the cookie. The information in the cookie can not be used by third parties to gain access to your account information.