> I poked through some of the listed extensions and most are basically bots that you can turn on that will crawl through LinkedIn pages very quickly and either collect info (like email addresses) or send out messages to other LinkedIn users.

I'm going to take the top ten from the list as an example:

daxtra -- Nothing like what you've described, plugin for a CRM

SalesloftProspector/SalesLoftCadence -- I don't see any crawling capability at all

discoverly -- Nothing like what you've described -- more like rapportive

Ecquire -- Nothing like what you've described, plugin for a CRM

Ebstabullhorn / EbstaSalesforce -- Nothing like what you've described -- plugins for Bullhorn and Salesforce CRMs only

ProspectHive -- apparently defunct, no idea

talentbin -- this is a social media aggregator

Entelo -- ATS plugin