Google released a statement revealing that they detected Skillern's child pornography through a technology called "hashing." Hashing is the process by which a document or image is converted into a single hexadecimal value that is unique to that document or image. Law enforcement authorities and the National Center for Missing and Exploited Children have indexed thousands of known child pornography images and created hashes for them. These hashes (as opposed to the images) are distributed to e-mail providers, such as Google to screen email and attachments. Apparently, Google detected one of the known hashes and alerted the authorities.
Read MoreAre 6-year olds more tech-savvy than you?
The federal law against child pornography requires anyone (including Internet providers) to immediately alert law enforcement if they knowingly possess or transmit child pornography. The law also requires the immediate destruction of the images. Anytime Google's system detects a "hash" tied to an offending image, it must immediately disclose that discovery to law enforcement.
No legal ground to sue in this case
"We will share personal information with companies, organizations or individuals outside of Google if we have a good-faith belief that access, use, preservation or disclosure of the information is reasonably necessary to: meet any applicable law, regulation, legal process or enforceable governmental request."
Read MoreHow much is your stolen password worth?
Although the child pornography laws are not specifically referenced, knowledge of the law is presumed by courts.
In addition to "hash"-based detection of child pornography, Google uses an automated system to scan email sent or received by gmail users for key words that are used to (1) create targeted advertising based upon the content of the e-mail and (2) build user profiles. Google also uses its automated scanning on email systems that it provides for Internet providers or educational institutions, although that information is only used to build user profiles, not create targeted advertising.
"give Google (and those [Google] work[s] with) a worldwide license to use … create derivative works (such as those resulting from translations, adaptations or other changes we make so that your content works better with our Services) … and distribute such content."
Not so fast, Google
Read MoreGoogle must face US lawsuit over consumer privacy
At this point, it is difficult to predict whether the plaintiffs will prevail in their case against Google. The trial court has only ruled that Google's defenses do not require that the case be dismissed. There will be extensive factual discovery and (if the case is not settled) a trial. Even after trial, there could be an extensive appeals process that could go all the way to the United States Supreme Court. There may be different rulings for individuals who choose G-mail as their provider, as opposed to those who (1) send email to a gmail account or (2) send email to an account that is not labeled "@gmail.com" but is administered by Google.
While the case is winding its way through the federal courts, Google has continued its policy of automated scanning of e-mail. So, if you notice that the ads you read online seem to closely track what you are discussing in your email, it is not an accident.