Hi folks. Sorry I haven't had a chance to respond. I've got some family in town for the holidays and have been tied up.
I stick to the advice in the article. The one thing I didn't mention was that I only do these references if the potential employee is cool with it. I ask the potential employee if I may check blind references and 95% of the time, they are cool with it...this happens toward the end of the process. Sometimes when that employee is not leaving their current employer, they ask me to only reach out to folks from their previous employers which is totally cool w/ me.
Once I get the green light, I go through my LinkedIn and find folks who I know who have worked with the candidate -- Boston's a small town and I don't have to look too far. I reach out and ask them about them. I must say, I do ask some pretty "open" questions and leave the door wide open for someone to say something negative about the person because I don't feel like a get a full picture about the weaknesses from the "given" references.
I totally agree with those who say it is not cool to do this without the employees consent.
I'll give you a case where this worked. Last month, we went through the interview process with someone from Microsoft. The person did well on the interviews (I've noticed that humans are getting better and better at interviews over time) and it was time to do the blind refs. The candidate was fine with us doing them. In this case, they were already out of Microsoft. I happen to know a bunch of folks at Microsoft. I talked to them and they all said the same basic things and were all pretty negative. We ended up passing. Personally, I think we dodged a bullet there.
This method is one I learned from vc's. In our venture rounds, I give them 5-6 references to call for me. They usually call them, but spend the majority of their time calling mutual connections that I didn't provide. Imho, this is smart! ...There was one venture capitalist who I thought went a bit too far. They called everyone they could find that had worked at HubSpot at one time, but no longer did. That's not a long list, so all of those folks were calling me asking, "Are you getting funded by ____."