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.\nThe majority of LinkedIn's members have joined at least one Group, and their experiences very likely vary. In general, the more effort you put into your LinkedIn Groups, the more value you\u2019ll see in return. Some users 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.\u00a0\n[Related: 6 LinkedIn tips to make your profile pop]\nThere are two sides to LinkedIn Groups \u2014 the things members appreciate and the annoyances they'd rather do without. Here are three things LinkedIn members identify as the major pain points of Groups. (And for the flip side, check out my companion story "4 things we love about LinkedIn Groups.")\n1) LinkedIn Groups are spam magnets\nThere's no way to sugar coat it. LinkedIn Groups are a magnet for spammers and self-promotional blowhards who could not care less about other peoples' time. Virtually everyone who joins a LinkedIn Group is eventually hit with a deluge of spam.\u00a0\nAmanda Orson, director of communications at EngineerJobs.com, says spam is by far the worst thing about LinkedIn Groups. "Moderation is time intensive, laborious, but absolutely necessary," she says.\nOrton thinks LinkedIn should develop better algorithms to filter and remove spam, particularly the get-rich-quick schemes and work-from-home spam that's present in many Groups.\nGroups can quickly turn into spam hubs if moderators aren't diligent about removing the problem posts. Irrelevant and loosely targeted sales pitches have no place in LinkedIn Groups.\n"Having the majority, or even half, of posts be self-promotional can basically make a group useless," says David Neuman, director of social media services at digital marketing agency Prime Visibility.\n2) Ads, self-promotion plague LinkedIn Groups\u00a0\nAdvertisements and self-promotional posts are routinely identified as major problems in LinkedIn Groups.\u00a0\nRob Chamberlin, cofounder and executive vice president of mobile virtual network operator DataXoom, says around 80 percent of Group posts he sees are overly focused on sales. "I don't think that is the intent of the Groups and believe group moderators need to be vigilant about controlling the content that their followers see on a regular basis," he says.\n[Related: 7 common mistakes job seekers make on LinkedIn]\nMarketers and sales professionals often exploit LinkedIn Groups to target thousands of seemingly relevant members. The end result, however, is noise that delivers little value or insight. "There is way too much junk \u2014 advertisements and questions that are really just thinly veiled advertisements \u2014 in LinkedIn's Groups," says Erika Flora, president at Beyond20.\n3) Top contributors manipulate LinkedIn Groups\nAnother problem with LinkedIn Groups is the counterintuitive means by which some members become "top contributors." Whether they intend to or not, many individuals game the system by posting relentlessly, and they are rewarded for those efforts without merit.\n"Just because you post a lot doesn't mean it's good or useful content, and a lot of it is the opposite," according to Michelle Messenger Garrett, a communications strategist. "I don't think [LinkedIn] should reward people for just posting or contributing. It should be based on what they're contributing."