yeah linkedin has tons of useless stuff.. i just keep my cv updated, trying to avoid reading news, or subscribing to groups. i've actually have found few jobs through linkedin posted job offers. Most of recruiters sending automated messages with invitations which I always decline. there's no way to communicate with your connected person.. no chat, no email provided.. it's easier to grab name and surname, and write PM through facebook. in my country linkedin is not so popular and recruiters actually writing nice messages with a good suggestions, that's how i've found a job in barclays. After living 2 years in netherlands.. i still get lot's of spam from there. Sometimes it's seems for me that only my country has a culture of recruiting, all others just spamming to get your attension.
