As with most things, the answer is it probably depends.
However IMHO the answer is NO, social media and networking when incorporated as a part of doing business is not a waste unless like anything else you let it become a waste of time.
I have chosen to leverage social media networking along with traditional mediums, venues, news letters, in person events, and other means of communicating, learning and doing business vs. ignoring it.
Does that I mean I jump on or join in every new social networking medium or venue? Nope, however I'm always watching to see where to invest time and effort and find the return or benefit.
Some observations about social media and networking include:
You get out of social media and networking what you put into it: When it comes to LinkedIn, Michael Naylor told me several years ago to get involved with and you will get out of what you put into LinkedIn (or other venues for that matter). Now about eight or nine years later, even despite the spam, I completely agree how true Mikes advise has been and remains.
Engagement, interaction, discussion (or debate) are all part of the discourse in and around social media and networking. Louis Gray who got me hooked on twitter and some other mediums years ago has a great blog post that unless you are engaging or interacting, you are not social networking. What that means is simply using social networking media and mediums as a broadcast or one way communication platform is just that, talking at vs. talking with or too people. Thus get out of your comfort zone, step out from behind your pulpit or podium and engage with audiences or participants vs. talking at them to get out of what you put into it.
Dont be afraid of joining different groups or venues, listen, lurk, observe, learn from others in the same or adjacent areas online, however also keep time in perspective to get other tasks completed. This also means you can build your own castle or venue for people to come to or you can do a hybrid including your own site(s) as well as taking discussions and conversations to where other audiences are.
Let me put this a different way, I like to fish and catch. Sometimes I know where the fish are based on experience and when they might bite, then there are other times when they move. This means knowing when and where to go to different locations to catch a fish or catch a conversation.
Building on the above, don't be afraid to get involved or start a conversation.
Sure on some venues you will get spammed and a bunch of responses that you might not like particular if venturing out away from the safety of your own castle or site. However use those conversations and engagements to learn and interact, see what is on people's minds or that they are interested in vs. what you want to tell them.
Where wasting time can come into play is trying to be part of every discussion, watching what everybody is doing or saying in all the various venues. For the trick has been to pick which venues are useful for where I want to invest time along with what I will get out of them in addition to using different tools to help find the applicable conversations and discussions. If you are not using things as basic as Google alerts you are probably spending too much time out looking for conversations or discussions, or, you are missing out on them altogether.
I have also noticed that there tends to be a correlation between those who are involved in one way communication and comment diminishing or dismissing social media and networking as a waste of time or not practical, hmm, go figure.
Otoh, I have also noticed those who tend to be involved in one way or non interactive discussions or that limit comments and discourse tend to also have lower numbers of followers, appear on fewer lists or get shared by others, hmm, go figure.
I have also noticed that some who do very well in cyberspace may not do as well in person and vise versa, however there are many who can do both. Likewise there are those who do well in columns that support interactive comments and those who do not.
Perhaps there is a hadoop big data analytics algorithm out there for someone who has lots of time to do some research on all of this?
What this all means is that to each their own, that is comfort zones. If your comfort zone and sphere of influence is in one way communication via print, online, video or what ever, then play to your strengths. Likewise, if yours is as a commentator or something else, go with it.
Leverage and get involved, don’t be scared, find your voice, engage, take part, however also be ready to be challenged while increasing your network of contacts, ability to learn and get out of what ever you put into it. Otherwise, stay in your comfort zone or within your sphere of influence.
As to if social media and networking are a waste of time and only for those who have nothing to do, well, if that is the case, last year was a banner year for me and my business. That is both in terms of activity, contacts, coverage, awards and accolades not to mention increasing discussions and experience in other areas as well as being involved in traditional media and venues or activities. I guess if that is the result of being involved or investing in social media and networking it is an honor to be among those who waste time and have nothing better to do.
Why do I take time out of my busy schedule to share this?
Simple, you get out of things what you put into it, and granted some will simply take advantage as opposed to contributing back, maybe they too will evolve to give back what they take out.
Feel free to engage or simply read and lurk, that option is all yours.
Ok, nuff said for now, have to get some other work projects done now.