The purpose of /which/ LGPL? And that's the thing. After GPL demonstrated that it had teeth and got some case law underneath it, the "family" of derivatives exploded, each one of them identifying as "open source" but each with their own additions, removals, modifications or other opinions on what "freedoms" they convey (mostly removals).
There are those of us out here who believe that the core purpose of all of these licenses were defeated a long time ago when all of this legal swizzling first began. I personally hate GPLv3, AGPL, LGPLv3, etc. with a fiery burning passion; thank god we were able to see some transformative projects emerge under actually free licenses before everything got ruined.