I've always rather liked LinkedIn because compared to services such as Facebook and Twitter it's actually useful. Unfortunately the company just did something that made me like the company a whole lot less: They restricted my account.
The reason given was that a number of people had received connection requests from me and indicated that they didn't know me. As a consequence LinkedIn required that I click-sign an agreement to behave and to get the restriction removed but there's a small problem with all of this; it was LinkedIn that made the connection requests on my behalf.
Sometime ago I foolishly allowed LinkedIn to access my Gmail address book which contained several thousand entries. I weeded out a number of people who I knew I didn't want to connect with but after working through the list for an hour or so, I gave up thinking that anyone who wasn't interested would just ignore the request and so I let LinkedIn just get on with it. and that was what caused LinkedIn to restrict me ...
So, LinkedIn gives you a way to connect with people in bulk but you can be penalized for using the feature ... a feature that they repeatedly encourage you to use. Dumb, dumb, dumb.
I'd be interested to hear if this nonsense has happened to you too.