LinkedIn’s Groups feature, which lets you connect with other users based on common interests, is one of its most popular offerings. More than 2.17 million Groups exist on the professional network, and that number increases every hour. Many Groups have tens of thousands of members, and it’s not uncommon to find Groups with hundreds of thousands, even a million, participants.

The majority of LinkedIn’s members have joined at least one Group, and their experiences very likely vary. In general, the more effort LinkedIn you put into your Groups, the more value you’ll see in return. Some see value immediately and are simply enthralled by the opportunity to connect with liked-minded individuals seeking common goals. The deluge of notifications, spam and content that sometimes runs counter to the Group’s topic and goals can rapidly turn others off.

There are two sides to LinkedIn Groups — the things members appreciate and the annoyances they’d rather do without. Here are four things LinkedIn members identify as the greatest benefit of Groups. (And for the flip side, check out my companion story “3 things we hate about LinkedIn Groups.”)

1) Build your professional network with LinkedIn Groups

Almost every LinkedIn Groups user I spoke with acknowledged the unparalleled benefit Groups can provide for networking. The capability to connect in a Group format with colleagues, experts and leaders in a particular industry can be invaluable.

[Related: LinkedIn love: The 17 countries with the most users]

“What I most enjoy about LinkedIn Groups is that they are a place for people to gather with a common goal, qualification, or to discuss a topic of shared interest,” says Amanda Orson, director of communications at EngineerJobs.com.

LinkedIn Groups also lets you connect with people you probably wouldn’t engage with otherwise. Requesting a connection with an individual is very different than simply joining a Group with hundreds of thousands of members. And Group discussions or posts can be the icebreakers that lead to more meaningful one-to-one connections.

“What I enjoy about LinkedIn Groups is the ability to connect a global network into a Group of similar profession, interest and passion,” says Pratibha Vuppuluri, founder of data analytics firm KeyInsite.

LinkedIn Groups bring together people with similar professional interests, and that makes a good, reliable network all the more important in these forums, according to Vuppuluri.

2) Share knowledge, stay informed with LinkedIn Groups

The capability to share knowledge and stay informed on the topics that are important to LinkedIn users is one of the most powerful benefits of Groups. It can be a great outlet for keeping up to date on news or asking for advice about a particular topic, according to David Neuman, director of social media services at digital marketing agency Prime Visibility.

Charles Krugel, a labor and employment lawyer who started a LinkedIn Group in 2009 that now has almost 3,000 members, says he finds Groups to be a great resource for information gathering and research.

“The primary benefit anyone should expect before joining is that they’ll gain new knowledge and insights, and also help develop their professional brand to further their career progression,” says Erik Mason, senior manager of public relations at enterprise disaster recovery firm Zerto.

3) Improve skills, build areas of expertise in LinkedIn Groups

LinkedIn Groups are a place for members to develop important skills and strengthen their areas of expertise. Members can learn a lot from what other members post and answer in Groups.

Lisa Rangel, managing director at ChameleonResumes.com and a moderator of a job seeker Group with more than 450,000 members, says it’s always heartwarming to see a fellow member achieve a particular goal after following another member’s advice.

“I love how the Group members help each other solve problems and educate one another on relevant topics,” she says. “It is extremely rewarding for members to provide meaningful guidance to another member.”

[Related: 7 common mistakes job seekers make on LinkedIn]

Answering important questions and providing relevant information to members in need of advice is a surefire way for Groups users to become valuable resources and experts in their fields, according to Rangel.

A well-managed Group empowers members to establish themselves as industry experts by encouraging them to ask questions, debate points, conduct research and identify subject matter experts around focused topics, according to marketing consultant Mark Amtower.

4) Develop leads for jobs, sales via LinkedIn Groups

The most savvy and prolific LinkedIn Group participants join different categories of Groups for specific needs. Some Groups are all about jobs, making them the ideal place to find and land a new gig. Other Groups are better suited for reaching potential referrals and leads for sales or new business.

Michael Raanan, a former IRS officer who now owns Landmark Tax Group, says he uses Groups daily to develop leads and referrals for his company. He also joined several Groups to continue building credibility as a tax practitioner by answering case-related questions posed by other members.”I spend a lot of time interacting with LinkedIn users that are excellent referral sources for the company, such as attorneys, financial advisors, insurance experts, escrow officers and tax-return preparers,” he says.

Groups also help members gain exposure and opportunities because headhunters are known to frequent Groups as they search for candidates, according to LisaMarie Dias, a social media and email marketing consultant and trainer. Dias also says Groups present members with great opportunities to demonstrate their expertise in forums that will be noticed by potential employers or recruiters.