In recent years, Princeton’s grueling final-exam schedule would goad students to post on websites where they vented about everything from homework to hookups. This year, however, two newcomers have bucked the trend: Tiger Compliments and Tiger Admirers, Facebook-based sites founded by a Princeton senior with the aim of “spreading happiness” on campus.

Many students are sending funny, altruistic, and often moving messages to people who have positively shaped their lives at Princeton — but without the writer’s name attached. “You are one of the most intelligent, passionate, caring, and fun people I know,” read a recent Tiger Compliments paean, written for Jamie Joseph ’13. “My interactions with you always leave my day brighter.”

The methodology is simple: Students fill out an online form with the name of the Princeton student they’d like to compliment, a link to the person’s Facebook page, and a brief message. The moderator and her team of helpers (who asked not to be identified to avoid discouraging students from using the sites) post the ­message, which is visible to all of the student’s Facebook friends.

Both sites have flourished: Tiger Compliments, which was founded in November, had about 2,600 student followers by mid-January, while the newer Tiger Admirers (for more romantic posts) had nearly 1,800 followers.

But if students respond so well to complimenting, why must it be done anonymously? For Alin Coman, an assistant professor of psychology, anonymity is the secret to the sites’ success. “It gives the impression that the community is valuing its individual members, it creates mystery surrounding the source of the compliment, and it builds on our desires to be admired,” Coman explained.

The Tiger pages follow a format developed at Queen’s University in Canada and adopted at several Ivy League schools.

“As lifelong high achievers, Princeton students are used to just being evaluated by grades and achievements,” said the websites’ founder. “I wanted to tell other Prince­tonians that they were appreciated for their friendship, their personalities, etc.”

Tiger Admirers runs the gamut from missed-connection stories (“I can’t tell if you sat down next to me because you were interested, friendly, or in need of a pen”) to surprisingly introspective ones (“My roommate is being cute with his girlfriend right now, and it makes me want to have something like that, because they love each other and themselves and I don’t like myself”).

Not all students are fans of being nice, however. And for those inclined to be more cynical, a pair of parody sites also made their debut: “Tiger Creepers” and “Tiger Back-Handed Compliments.”