Adobe Lightroom Exchange
lightroom-news.com/2008/06/10/adobe-lightroom-exchange
From the page
Saved with the link. Notes from 2007 to 2016 are mostly the page's own words, so this is probably an excerpt.
When you look for plugins and addons to Adobe products, most users would be encouraged to go to the Adobe Exchange site. This is where developers would add and advertise their product, be it free or commercial. Up until recently this wasn’t possible for Lightroom users, but now we finally have a Lightroom Exchange. The featured product there currently is SlideShowPro for Lightroom, but there are many others there from such well known figures ase Matthew Campagna and Jeffrey Friedl. As a user, you should check out what’s available. As a developer you should be adding your product to the list. I know I will be.