First of all, what is Facebook? Open your phone. It's the blue one; the OG of Internet-based life-hyping, and it deserves your respect. Facebook is the crystal ball your mother uses to keep tabs on your life. Facebook is how you get away with forgetting to notify an important person of a major life event. It is also an information-gathering portal whereby you can learn a wealth of interesting things pertaining to the person you're dating.
And yet: There are rules. One can't just "friend" someone before the first date. You're not friends yet. You're not anything more than potential catfishes. Proceed with caution at all intervals. Lest we forget that once your date lets you in, you've let them in. You also can't wait until you've been dating for an extended period of time. Think of the valuable resource you'd be wasting! For shame.
You shouldn't be expected to navigate these mystifying waters on your own, though. You could run out of battery life for goodness sake. Hence, you may reference this comprehensive guide as its terms apply to you, so that you can know when the actual right time to add your date on Facebook is.
1. Curiosity is present: This is going to take a date or two. One can't rush to snap judgments, nor can one spend seven dates figuring out this Rubix cube of a human being. Things move quickly in life. If you suspect a relationship might materialize, feel free to add this person on Facebook no sooner than the third date, but no later than fourth. This will allow you to verify facts, inspect genetic qualities of family, and thoroughly evaluate all seasons of their wardrobe while still falling in the zone of "I can just stop texting you back if I want to."
2. Actual romantic feelings are present: Proceed with utmost caution. In the presence of the illusive "good" date, one must shelve one's curiosity in favor of actual manners. Adding a date on Facebook suggests a familiarity that is present during face-to-face contact. Without this, screen-to-screen contact may prove a bit awk. You must not add your date on Facebook until you hear these words and only these words in this particular order: "So, what do you want to do this weekend?"
3. You suspect your date is a vampire: If vampiric suspicion is present, please feel free to add your date as soon as two hours following the first date but no more than 27 minutes into the second date. In such extreme circumstances one wants as much information as is available. You need to know when they stopped showing up in their own selfies. Also there's the matter of living quarters. If they sleep in an inverted position from a rod in the closet, you're so going back to your place. See the intermediate chapter on supernatural courtship, section B5.
4. Your date is hiding a secret twin: Did they return from the bathroom way too fast? Did they order you a martini when you've had nothing but red wine for the last two hours? Was that freckle there before? WAS IT? Toss all formality aside and dig in. Find evidence of twin, present it, exit. Screenshots will assist you in building a case in court, remember this.
5. Your date adds you: Whaaaaaaat? This breaks from protocol altogether. If this person adds you on Facebook, you're on your own. We've never seen this behavior before and we find it suspect. This is very unorthodox behavior. Very unorthodox. Your date is probably some sort of unicorn. All those with equestrian skill should feel free to proceed, those without abort mission.
6. Your date works at an app: Startup employees are the holy grail of laptop-based information gathering. This is one situation where you don't need Facebook. The internet is your Facebook. After you've completed step 1.7 by using your magnifying contact lens to learn their last name and DOB from when the bartender carded them, commit said information to memory; then, consume no more than two drinks, and return to the cave to engage in research. Google that shit.
7. Your date doesn't frikkin have Facebook. Is your date 18? Are they actually 18 years old and only capable of communicating via (for f*cks sake) SNAPCHAT? If you must date someone who doesn't have Facebook, first make sure you haven't just imagined this date, and then, with great skill, get them to show you their Instagram. "Do you have any pets?" "Where does your family spend Christmas?" "Do you like to cook?" All reasonably photographable scenarios that have high odds of giving you a peek at the goods. And by goods we mean their Instagram account name. Once you have this, you may gather all information required using no more than a quick trip to the loo. Unless their account is set to private, in which case do not ever see them again.
Your date looks like Chris Evans
. After the fifth date.
Your date is Chris Evans
. [Standing slow clap.]