Though LinkedIn may be a top social network, it's probably not the first place a musician might go to connect with others. Sure, business people and people looking for jobs should be on LinkedIn, but artists? While it is true that LinkedIn is not for everyone, its status as a lower noise space for business networking is definitely useful for the artist who wants to better understand the business world and take advantage of music opportunities being shared on LinkedIn.
LinkedIn is designed in various ways to reduce spam and noise primarily by putting certain limits on communication. You can invite people to connect but direct messages to folks who aren't in your network is fee-based. You won't be suddenly added to groups or be barraged by event invitations. Though such efforts haven't eliminated spammy behavior, it does mean that the possibility for actually breaking the ice is increased.
LinkedIn offers a couple of resources for learning that can also support networking. LinkedIn's Answers provide an opportunity to ask questions and get answers though such services are always hit and miss. For example, if you're trying to figure out how to take your music brand into the fashion arena, it would be worth putting out some questions about aspects of the fashion industry you don't understand. In the process, you may be able to identify allies in other industries as both learning resources and potential partners.
LinkedIn's group feature is focused on networking within an industry in a conversational manner. Groups are a place to make one's presence known and to identify possible allies in a particular industry or area of interest. They give you a simple context for evaluating feedback from individuals and for finding trustworthy information sources. Music opportunities get posted in groups so that's another reason to take a closer look at the exchanges going on within the group.
However, get set for some sorting out. Though LinkedIn may be a more professionally oriented social network, that doesn't mean that friendly feedback is always going to be of use. In fact, some folks seem more than ready to help even though their knowledge is speculative!
LinkedIn offers a variety of premium options, but the free version offers access to groups and Answers and should be more than adequate to evaluate whether or not LinkedIn is a good fit.