All the time. I get recommendations from past customers on Linkedin for future customers to see. It has generated business for me. Well worth it. YOU DO NOT HAVE TO BE A PEDOPHILE. Just smart with generating more business.
I must agree with Chris1971. Put another way - as an electrician, which I am not BTW, you may say "why would I carry a hammer, I'm not a carpenter" but there are occasions where it comes in handy and helps you out. Linked-In got me my job, with help from a guy who I hadn't been in touch with since we were in the Navy. His buddy (VP) was able to see my resume/experience and it helped in his decision to call me versus just writing me off as someone who was just a friend of a friend...I may not ever "use" Linked-In again but it worked and who knows.
FB really is a "social" site but for all the "word of mouth" guys, here's your word of mouth opportunity! Almost everyone I know is looking for an electrician, plumber, roofer, etc. quite often...use your trademark avatar and just monitor what you say so you're not too goofy.
An old HS friend (realtor) helped me get my house. Would rather use them than someone I didn't know...
Sure, these sites aren't going to be your only tool by any means and they could never take the place of this forum, but why not use everything available to you? Just saying...