College students — cash strapped yet always hungry and plugged in — are a key demographic in the business plans of most retailers, food companies and technology operators. Whether as a core segment or a test audience, the 18-24 age group is a proving ground for brands looking to create brand loyalty — during their college years and beyond.

In different ways, the following nine companies have catered to this hot market segment, and have acknowledged publicly how the group helps boost their business.

Read MoreInsomnia Cookies caters to late-night munchies

Whether cookies, burritos or mobile apps, these companies have made themselves nearly invaluable to students — and have been rewarded with the revenue that comes from tapping a ripe market for feeding students' needs.

— By Drew Casey, special to CNBC.com

Published on 26 Dec 2015

Nothing says "college" more than a late-night bakery that stays open until 3 a.m. Founded out of a college dorm room in 2003, Insomnia Cookies now has over 70 locations, a majority of which deliver to universities.

"Our original business model had us opening later in the day and delivering until 3 a.m.," according to the company's senior director of marketing, Megan Bruton. "That is music to any college student's ears after a long night of studying or being out until the bars close."

While the focus may seem to solely be on college students, the company also acknowledged that it is not mandatory that locations be located near college campuses. Because, hey, who doesn't love "warm, delicious cookies," especially in the middle of the night?

While the Mexican food giant has had a tough run in the news lately, the fast casual chain has ridden a wave of popularity with college students.

"Our first restaurant was adjacent to the University of Denver, and our second was by the University of Colorado medical campus," Chipotle's communications director, Chris Arnold, said. "Since then, we have opened a number of restaurants that are proximate to colleges and universities, and we have always been popular among students."

Aside from proximity to campuses across the country, Chipotle also connects to students through other programs. Some locations allow meal plan cards to be used as payment, while some campuses can utilize a delivery service established by Chipotle, in a partnership with Tapingo, an online food delivery app.

Like many of its competitors in the on-demand car service business, Lyft has a big following among college students (and working professionals). As both customers and employees, college students have been key to the company's early success.

"Many college students rely on Lyft both as a safe, affordable ride home as well as a flexible economy opportunity," the company told CNBC. "Students have been instrumental in Lyft's community growth as passengers and drivers."

Lyft said that 80 percent of its drivers work less than 15 hours per week, affording a number of college students the opportunity to work part-time for the company during the academic year. Additionally, some students serve as paid college ambassadors across the country, helping to spread the word about Lyft on campuses around the country.

College students always seem to have the edge when it comes to social media (Facebook began as a dorm room start-up), and that is exactly the case when it comes to professional social media site LinkedIn. Currently, over 40 million students and recent graduates utilize the networking platform.

"We have amplified our student-focused efforts in recent years," a company spokesperson said. "Recently, we have launched products aimed at helping students to build their professional brands."

LinkedIn has launched a Student Publishing website, and is in the midst of a LinkedIn Placements pilot in India. These initiatives are part of an effort to aid would-be professionals in developing their career and helping them find their first job.

Ride-sharing powerhouse Uber continues to recognize the significance that college students play in their business success. According to the company's research, 11 percent of Uber's drivers are students.

"Students find the Uber platform to be something that works within their class schedule," David Plouffe, Uber's chief advisor, said in a recent news conference call. "[It] also allows them to make additional money, whether that's to help pay for college, for room and board, for expenses [or] spending money."

Since December 2014, Uber's under-30 driver population has also grown from 19 percent to 23 percent. According to Plouffe, the growth suggests that young professionals are continuing to drive for Uber after graduation to supplement their initial income.

The popular online food delivery service GrubHub has made a splash with college students. After acquiring Campus Foods in 2011, the company immediately jumped into more than 300 college markets, a chunk of their more than 6.4 million active users.

Overall, GrubHub is now in more than 900 U.S. cities, many of which are "well-known" college towns, according to the company. GrubHub has also started a bigger focus on college students from a brand awareness perspective — attending tailgates and offering game-day delivery options at schools such as the University of Wisconsin and Virginia Tech.

"While it's easy to assume that a majority of them are hungry college students, we have a wide variety of customers including but not limited to, business professionals, working parents and people who are looking for new takeout options in their neighborhood," the company said.

There's no question that college kids love electronic messaging. In that vein, GroupMe is just one of many mobile applications available to serve 21st century messaging needs.

The company, which was bought by Microsoft a few years ago, recognizes that groups are prolific on college campuses and that communication can sometimes be difficult in the midst of students' busy schedules. GroupMe also currently promotes its brand to college students, organizing events and various competitions on campuses across the country.

"We know college students are mobile-first and use their phones to interact and share," the company said. "Our team is constantly innovating to make it easier for our college student groups to share, laugh and chat with their groups, through features such as group messaging, GroupMe over SMS and cross-platform availability." GroupMe is available on iOS, Android and Windows Phones.

The future of broadcast television is clearly as viewers cut cords and devour streaming media. But one product that might find a happy medium — and attract more college students in the process — is Slingbox.

Slingbox allows individuals to tap into their home cable or satellite television subscriptions from anywhere in the world, using a laptop or mobile device. There's no cost for the service, except for the initial purchase of the unit.

"We find it attracts college students because of its budget-friendly and all-access appeal," Mark Vena, vice president of worldwide marketing EchoStar Communications, which owns Slingbox, told CNBC.

"Oftentimes, college students who live in residence halls are restricted to the channels provided by campus housing, and those who live off campus don't want to burden themselves with a cable bill of $100-plus each month," he said.

Since popular file hosting service Dropbox hit the market in 2007, college students have been key to the start-up's success. Dropbox has been so successful within that demo that some schools, including California State University, Fullerton, have partnered with the company through Dropbox for Education for the entire university community's usage.

"College students are huge fans of Dropbox," the company said. "It helps them make the most of their time on-the-go, collaborate on group projects, run student [organizations], search for their dream job or internship, and ultimately stay organized through college and beyond."

According to the company, college students and faculty store over 22 million GB of schoolwork, e-textbooks and photos on Dropbox. They also send over 94,000 shared folder invites to collaborate with others each week, making group projects easier to facilitate.

"At the end of the day, college students love Dropbox because it makes their lives easier," the company said.