I deleted my LinkedIn account last year because I got tired of dealing with spam emails from them and people bugging me to endorse them for skills. I still get emails from LinkedIn telling me someone would like to connect. For a site which is supposed to be about building professional connections I find them horrible to deal with.
I had a traditional, i.e. one that wanted salary history and other non-relevant information, recruiter tell me during a discussion that person x at linkedin says you should provide this information.
This is when I realized that linkedin in not about professional relationship but about recruiting folks and that recruiters will find it most useful.
As I can find a job without a recruiter, linkedin's value to me is close to zero.
Endorsements seem automated to me, and I almost feel like I'm taking crazy pills. Distant cousins endorsing you for Ruby? There's no way they actually clicked that button. I feel like LinkedIn is generating those as well, as a means of getting back on their platform.
Endorsements always seemed a bit off and it wouldn't surprise me if they were automated. I had an ex-colleague repeatedly contact me about endorsing him as he had endorsed me. At that time I hadn't looked at LinkedIn in months so I had no idea why he'd endorsed me. I got the impression that the site had suggested he do it and now obviously I should return the favour. All very annoying and one of the main reasons I closed my account.