This data includes your name, your date of birth, your Social Security number, your address, your phone number, and so on.
The information about what you do online includes what searches you perform, which websites you go to, what articles you read, and even what items you buy online.
Most of these dating sites offer a free membership, which may not allow communication with other members, but do allow viewing other member profiles.
That's a major turn off, and something you should know from basic common sense. Bringing someone with you without telling your date, can create an uncomfortable situation for the person you're meeting, which can cause an otherwise good date to go bad.
Don't think bringing someone with you is "no big deal." It could very well be a big deal to the person you're meeting. If someone wants to meet you, but doesn't have a cell phone or doesn't want to give you their phone number, my suggestion is to not meet them.
But if you do, don’t say something stupid like you’re already dating someone.
It’s not believable…that’s really your situation, then why are you on the dating site? When you're talking with someone from a dating site, on the phone, or in person, don't ramble on and on endlessly about yourself. If the main picture on someone’s profile is appealing to you, and you’re thinking of contacting this person, have the common sense to look at ALL of their pictures, and anything else on their profile that may be important to you, BEFORE you decide to send them a message. If you receive a call from someone you’ve given your number to, and you can’t talk to them at that time, then YOU should return the call. They took the initiative to make the call, and obviously didn’t know it was a bad time for you to speak, so YOU should have the decency to make the return call. If you're going to be bringing someone with you on the initial date, TELL THE PERSON YOU'RE GOING TO MEET BEFOREHAND.