From what I have heard, social media is used but still on an early-adopter basis in the fluid power industry. It will grow but I am not sure at what rate.
Companies are signing up for Facebook pages and individuals and company representatives signing in as companies are using Twitter. LinkedIN is growing but I am not sure that where it will be best used. Hydraulics & Pneumatics has over 2,000 members in it's LinkedIN user group.
My advice is to get involved in Social Media. The many programs that offer you the opportunity to participate offer exposure for your company and products. It does take person hours though and a company needs to have a strategy.
I don't think that Social Media will replace face-to-face meetings, telephone conversations, or even e-mail. It is another tool that, if used wisely, can be benificial.