Around the middle of last year, LinkedIn announced that hashtags were back - at least they were on mobile devices where you could tap on a tag and it would run a search round that word.

It now seems that hashtags are back on the desktop site with the same functionality.  Simply type in a tag such as #Leadership and choose the Posts tab and you will find content that has been tagged accordingly.  

This is still very new so some individual experts are dominating search results for specific hashtags.  In short, start using hashtags in your desktop posts and your visibility will be raised in search results on LinkedIn.