If you've held a job for more than a few years, especially the kind where you had to write (or borrow) a resume to qualify for an interview, you've probably had to list some "references" as well.
A professional "reference" is supposed to be someone whom you've known, professionally, long enough to tell a prospective employer good things about you. Things like how well you work with others, your skill set, types of projects or operational work, and so on.
A professional reference is NOT someone you worked in the same office with, but didn't interact with every day. Nor is it one of your drinking buddies.
I'm not sure why, but I've been asked to give permission to list me as a reference for more than a dozen current and former colleagues. I say that because my professional career path hasn't been the shiniest example for others to follow. In some ways I consider myself the guy walking backwards through a minefield, giving out advice on how to detect mines. Yeah, I saw that episode of Benny Hill.
The problem comes into play when someone you're friendly with, maybe really good buddies with, asks you to be a reference for a job they're applying for; but you can't honestly say you worked directly along side this person enough to vouch for every skill the new job is asking for. Maybe you didn't work with this person directly at all. The risk you take is that you may say "Sure, this guy/girl is an awesome ___. I'd hire them in a heartbeat.". Then they get hired and things fall apart. Now you're reference is devalued by having vouched for someone that just didn't cut it for them.
Granted, this is a risk for any such circumstance, but you greatly reduce that risk when you stick to your guns and only agree to vouch for people you truly KNOW about on a professional level.
This spills over into LinkedIn skill recommendations as well. I can't count how many people have tagged me for a skill I barely know. VMware ESX? I played with it. SharePoint? I can install it, configure it, build some sites and libraries and post pictures of cute animals. After I started seeing notifications that so-and-so tagged me as an expert on these things, I began to go back and remove those items which I consider myself to be marginally skilled at best.
To be fair, it's not really something I can blame on my LinkedIn network, it's just everyone trying to help each other out, and that's very much appreciated. But it also puts them at risk of damaging their street cred by saying I'm a pro at something that I'm really not that well-versed in. To mitigate the chances of hurting their good intentions, I'm making the effort to clean up my skills list. I think it's a good idea.
Back to ironing shirts for Monday staff meetings. Cheers!