Stanford University's student union was packed with undergraduates and representatives from start-up companies at a job fair last Thursday.

But it was hard to tell the two groups apart.

Circulating the crowded space of "Start-up 101," part of the larger Entrepreneurship Week occurring on campus last week, some students were older than the company founders -- who were also their classmates.

The two groups mingled fluidly as old friends greeted each other.

The event, which attracted close to 100 start-ups, showcased the close ties between the university and the world of Silicon Valley.

Stanford's 14 pro-entrepreneurship groups train ambitious students to found their own companies. In turn, those companies came to Thursday's fair looking for interns and staff.

Jeff Seibert, 22, stood at the table for Increo, the start-up he founded last spring with fellow students Rebecca Illowsky, Kimber Lockhart and Ray Thang.

The Web-based program helps people compare their ideas by using an algorithm to link similar concepts, according to Seibert, a senior computer-science major who will graduate in June.

His start-up know-how stems partially from his participation in Stanford's Mayfield Fellows Program, named for venture-capital firm the Mayfield Fund, which pairs students directly with a venture capitalist as a mentor and arranges an internship at a start-up firm.

The group that arranges the fellowship, the Stanford Technology Ventures Program, also organizes the Entrepreneurial Thought Leaders lecture series, which invites Valley luminaries to lecture and arranges networking dinners thereafter for students.

Seibert has been to the last 86 lectures and networking dinners in a row, he said.

Increo has gotten funding offers from venture capitalists he met through the series, he said.

Stanford's connection to Silicon Valley wasn't lost on Rick Pernikoff, who stood by the table for Loopt, a cell-phone application that uses GPS technology to show callers where friends are.

Pernikoff dropped out of MIT after his sophomore year to move to Palo Alto and join high-school friend and Stanford drop-out Sam Altman in running Loopt.

Stanford is more capitalistic than MIT, according to Pernikoff, now 22 and heading up product development.

"Here people are taught how to take an idea and drive it to a business," he said, noting MIT's focus is on "innovating for the sake of innovating."

Outside on the balcony was further evidence of the business drive: a table for Cooliris, founded by a Stanford student in his senior year, along with a graduate and a local entrepreneur.

Near piles of neon sunglasses, flat-screen TVs were set up in reference to the company's program called PicLens, which allows people to view pictures in three dimensions. Students and company representatives donned the day-glo shades as they stood chatting in the afternoon sun.

Cooliris co-founder Josh Schwarzapel was a senior and a Mayfield Fellow last spring when venture-capital giant Kleiner Perkins Caufield & Byers -- whose U.S. office lies just off campus on Sand Hill Road -- awarded the start-up funding.

Cooliris employs 30 Stanford students as interns and five of its 10 full-time staff members are Stanford graduates, according to Schwarzapel, who stressed that as the leader of business development, he was merely one of a larger team.

Trevor Cornwell, founder of the start-up Embarkons, came to the fair to find business-savvy students, he said.

"I actually am desperately seeking Stanford," he said.

Cornwell moved his company from Washington, D.C., to downtown Palo Alto because good ideas can make it big here, he said.

"This is the Hollywood of ideas," he said. "Here, the coders are the Brad Pitts."

And of drop-outs such as Pernikoff who ditch campus to strike it rich, the middle-aged Cornwell said: "They're the über-people."

Cornwell's Embarkons is a social network that connects people through ideas, allowing users to search and rate each other's concepts, he said.

If that sounds familiar, Embarkons and Increo weren't the only companies with similar ideas. Start-ups run by those from within and without Stanford's elite environs presented overlapping visions at the fair.

Stanford-rooted Loopt's friend-finding service had already been tried -- and abandoned -- by Jared Kim, a 20-year-old UC-Berkeley drop-out heading his third start-up, WeGame.

Kim started a text message-based friend-finding service on Berkeley's campus but it didn't catch on because students didn't want to pay for the messages, he said as he hovered near WeGame's table.

Asked whether the Berkeley-Stanford rivalry mattered to him, he laughed.

"Stanford students are smart. ... So are Berkeley students," he said.

The fair wasn't for everyone, however. Not every Stanford student takes courses that groom him or her to become a junior executive.

In the midst of the social buzz hanging over the fair, junior Kenneth Lam side-stepped several people with gold-lettered "alumni" tags on his way to the exit. Weighed down by a stack of fliers and a smattering of freebies -- candy, a T-shirt -- Lam was nonetheless leaving without thrilling prospects, he said.

Hunting for a summer internship, he instead spent the afternoon watching faces fall when he said he was a chemical, rather than an electrical, engineering major.

"I found a lot of stuff that made me feel like I'm not qualified," he said.

Junior Priyata Mehra said she was cruising the fair in hopes of learning about alternatives to a summer internship in consulting or investment banking, popular choices among peers.

She hadn't before explored the idea of joining a start-up, but it occurred to her that Stanford is in the middle of Silicon Valley, she said.

It would be a shame not to take advantage of that opportunity, she said.