I agree, this is a mistake, however it probably makes perfect sense to those who will sign-up. Now they have a major player condoning unsolicited commercial email (UCE or SPAM.)

I'm glad I closed my account when I did. Hopefully my account info has been purged. LinkedIn has been in my spam filter for several years.

If it becomes a real nuisance it'll quickly become a turn off for LinkedIn members. It's already a challenge with the fake users on there.
I'm going to wait and see how this works out before passing judgement.

This is a new frontier for Brand Building, Content Marketing & Relevant Link Building.

This is a new frontier for Brand Building, Content Marketing & Relevant Link Building

How so?

Content promotion
LinkedIn Sponsored InMail gives content marketers the ability to promote their content directly to specific influencers and relevant groups.

That's just the beginning!

I suspect this will fly over the heads of those on the coding and creative side of Internet work, people who do not engage in promotion or buying advertising.

But for those who are involved in promotion, this is interesting news as it opens up a new frontier to explore for promoting content, ideas and products. And that is when those on the coding & the creative side will get involved in the role of pulling the buggy while the promoters hold the reins.

Sorry, I'm not sophisticated with all this. Buggy or not, anything unsolicited I just see as spam.