"If I'm never going to work with them, I don't care, but I tend to not really like to talk about it," Rosenblum said. "I have a friend I went to college with, and she works in fashion. I kind of know that we're never going to work together, and it's interesting to get her feedback [on salary]."
Sharing salary information sets up a competitive environment she'd rather avoid.
"You start second-guessing where you are," she said.
Rule #2 (also known as caveat to Rule #1): Unless you want to.
Despite Rosenblum's own hesitancy, people in her office do discuss salary, though in very vague terms.
"We did get our bonuses, and there was vague talk: 'I guess I can't pay for this now,'" she said.
Kate, 23, who works in communications for a financial firm, said that some 20-somethings' openness isn't necessarily due to more access to information.
"I tell everyone what I make," Kate told me in an instant message. "Well, I don't tell everyone, but when I'm having a frank discussion about jobs and I need real advice, I don't hesitate to just level with a friend or colleague."
She likens salary-sharing to a rite of passage.
"I think income to the generation right out of college is like a shiny new toy: They want to take it out and show it off to everyone," she said.
But later in life that changes, said Kyle Wortham, 37, a senior brand manager at Pabst Brewing Co.
"I don't talk about my salary," he said. "[When I was younger] I don't think people were so protective of that information. As you advance, it becomes a little more secret."
Rule #3: Do not talk about salary with people you're dating.
For the truly tactless, this rule is worth repeating.
Laura Fenton, 27, a New York-based consultant for a nonprofit organization, says that she has experienced far more issues by discussing her salary with a romantic interest than with her friends.
In one long-term relationship, Fenton knew she made more money than her boyfriend, so she delayed talking about money until a year into the relationship.
"I definitely would say I regretted talking about salaries with him," she said. "There was an expectation at times that I should then therefore pay for more stuff."
Conversely, she also went on a few dates with a longtime friend. For years, he had never talked to her about money -- until the dates.
"He makes a lot of money, and he feels like this is alluring to women, where to me, it seems very unattractive," she said.
Fenton recently changed careers, and with the switch came questions.
"When I tell people that I make less than before, they're surprised someone would do that. Then they ask me how much the pay cut was," she said. "I say, it's really none of your business."
For many, the money talk between significant others remains significant.
"I haven't even told my [live-in] girlfriend what I make, and I don't know what she makes," Wortham, the brand manager for Pabst, said.
As for my own rude awakening via instant message, I wonder whether this newfound openness isn't detrimental: When Jane revealed her salary, my stomach dropped into my shoes. In a high-powered media world, was this much of my self-worth tied up in dollars and cents?