First pulls in information you provide (through CSV uploads and your email, and phone sync) and also supplements some information. We do this to improve your experience and to help you keep your contact information in First accurate and up to date.
However, you are the true expert about your contacts. If you see something wrong you can update the contact details by using the guide here.
For more context on why this happens it is important to look at each data element separately:
For a lot of the contacts that we get from you we don't actually get their full names. For instance contacts in your phone may just have a first name or nickname, and contacts in your email might have no name at all - just an email address. Instead of placing the burden initially on you to find the full names, we run a search against a massive database and attempt to find the right person. More often than not, we succeed, our system seamlessly fills in the details, and you probably don't even notice. But sometimes we get it wrong. We have made it easier than ever to update contact details as outlined here.
We attempt to help you find addresses for your contacts to help you fill out your database. We get some addresses for your contacts when you sync your email and phone and we get some more if you send us a CSV for your contacts with addresses already appended. We also search nationally for known addresses for your contacts and present these to you in the application. These addresses are not necessarily properties that your contact has owned, but rather properties where they have some kind of connection (resided at or received packages or mail at in the past). If a property has "added by First" next to it, generally it came from us. If not, it came from you.
Again, you are the expert when it comes to your network and you may have access to more local property information that we do.
Phone Numbers and Emails:
We do not append phone numbers or emails. If they are in your account we pulled them from one of the data sources you synced or uploaded. Regardless, we are here to help!
Because we pull in data from a variety of sources (and because you may have duplicates already in those sources), there will be some duplicates in your account. We only merge duplicates if we feel confident they are the same person. Otherwise, we leave it to you to indicate when there is a duplicate. We take this approach because if we merge contacts incorrectly it can sometimes have embarrassing consequences. It is very easy to merge duplicates once you have found one. Just click on the flag in the top right corner of the contact card and press Duplicate. Our team will get to work to merge that contact.