I'm not sure how I feel about this new type of job search. Like speed dating it feels a little degrading. However, a casual relationship with a company you are interested can pay dividends. The first science job I had wasn't advertised. I heard about it from an employer I was talking to about getting into the field who knew a guy that used his service that was looking for someone to help out with his research. If I think of these job sites more like that, the possibility of learning more about a particular company or job title, there may be more benefit in them and who knows where a ten minute talk might lead?