SAN FRANCISCO (CBS SF) — A new app that pulls information off the internet to improve the average email has even the creator calling the new technology “creepy.”

Drew D’Agostino is the man behind “Crystal,” something he calls the biggest thing to hit email since spellcheck.

“Crystal tells you how to communicate with anybody.  And, to get that information, it detects information written by you, or about you online,” D’Agostino said.

For example, if someone needed to send an email to someone, “Crystal” would scour the internet to find whatever public information is out there, and develops a character profile.

“That’s where you get these insights that say, ‘this person really likes short emails, and they get right to the point,’ or, ‘this person needs a lot of detail; this person likes structures and rules; that kind of stuff.’” D’Agostino said.

The app will even tell users how to write, coaching them towards an email worded specifically for someone else’s communication style, something D’Agostino says “is an example of how technology can bring the personal even more into the focus.”

But, even D’Agostino admits the app may seem like a violation of privacy to some.

“When you first see it, everybody has this weird reaction of, ‘this is kind of creepy, but this is also really powerful.’”

“Crystal” doesn’t perform any special kind of background check, only using information that is publicly available.  The founder says the accuracy rate is about 80-percent.