I love that this "perk" exists in my workplace. These shared articles are often items I would not grab to read myself. Thus, my boundaries of work knowledge are expanded. I tend to read from the same journals over and over again, so it's nice to be reminded that there is other stuff out there. Too often, I can get bogged down on what I have to know for work that I forgot there is so material that might be useful. These shared articles help me find the broader picture in library work.
In the same vane as the lunches, I love it when fellow librarians share links and titles to articles in their blog posts or through list-servs. You never know what is going to pop-up or the discussion that might follow. There is a whole wide world of professional reading, so seeing something recommended is a nice way to get a handle on it all.
One of these days I'll make it to a lunch discussion, and who knows, maybe I'll discover even more articles I might have missed.