A fateful letter with highly sensitive information that would affect Meggie Ranheim’s sleep schedule, social life and everyday routine for the next school year arrived recently in her mailbox.

It was her roommate assignment for her freshman year of college.

“I was pretty nervous,” said Ranheim, who will attend St. Olaf College in Northfield, Minn. “I thought it would be some wretched person I would be stuck with for the entire year.”

That day, the 18-year-old from Eagan, Minn., exhumed a then-faceless and voiceless Nebraska teen from the depths of a cyber-abyss in hopes of alleviating that fear.

Many other freshmen are doing the same, sometimes with mixed results, as the popularity of social networking sites continues to increase.

Often, parents are doing the same kind of investigation, using popular Web sites such as facebook.com and MySpace.com to vet their child’s roommate-to-be. Some are registering displeasure over what they find to college housing officials.

In Ranheim’s case, the profile on Facebook.com was set to private, so she could see only her picture: a face obscured by a gas mask.

“I thought maybe she was one of those alien conspiracy people or something bizarre,” Ranheim said. “It did concern me at first.”

Ranheim shot off a cheerful message and requested to be the girl’s “friend” on the site, which would give her access to the page.

No response. A week went by.

“I was a little worried,” Ranheim said.

Eventually the roommate wrote back. She was away at camp with no Internet access. The girls quickly bonded over their love of National Public Radio, tea, recycling and the clarinet.

Ranheim felt that she lucked out.

“Facebook and MySpace present multiple challenges and opportunities,” said Aaron Macke, director of residence life at the University of St. Thomas.

THE UNIVERSITY STARTED getting calls in 2005 about disconcerting content on roommates’ Web pages, mainly involving foul language or pictures with liquor in them, Macke said.

Addie Gorlin, 18, of Hopkins, Minn., was on the lookout for anything tawdry on her roommate’s page when she looked up the Maryland youngster on Facebook.

“None of her pictures were of her throwing up on the floor,” said Gorlin, who will be a freshman at Dartmouth this fall. “Some people do have that in their pictures.”

Calls to St. Thomas, averaging about five to 10 a year, have not skewed toward any demographic, and are split between students and parents, Macke said.

Chris Magnusson of Hibbing, Minn., is among the parents who haven’t hesitated to check up on their children’s roommates. Last year she looked up her son’s three roommates at the Minneapolis College of Art and Design and found “pretty tame” pages.

“[My son] couldn’t believe I would do it,” said Magnusson, whose son waved off any interest in checking out the sites himself.

Last year, concerns from a student about a roommate’s social networking page led St. Thomas officials to change room assignments, said Macke, who didn’t want to offer specifics of the situation.

“I don’t move someone because of something on Facebook,” said Mannix Clark, associate director of housing and residential life on the University of Minnesota’s Twin Cities campus. “We just don’t have the space for that. I don’t find it frustrating. It’s probably more frustrating for the person on the other end.”

AT ST. THOMAS and the U of M, students answer six questions about personal habits from smoking to cleanliness when applying for on-campus housing, a traditional starting point for putting together roommates. A computer matches up thousands of freshman and transfer students based on the answers.

The U also has a more extensive questionnaire offered only to those who commit by an early deadline to attend, an option that allows students to pick their own roommates.

Clark and Macke said their schools strongly urge students to call their roommates. Neither has a policy on students checking social networking sites.

Freshmen-to-be said it makes sense to start out by checking Facebook and MySpace because it’s quicker and easier than making a phone call.

More personal communication typically follows.

“It was almost just like a reflex to go and find [my roommate] on MySpace,” said University of Minnesota, Morris-bound Amber McMahon, 17, of Buffalo. “I think MySpace is easier because then I can think about what I’m going to say instead of blurting something out [on the phone] and have it sound stupid.”