From American Birding Association's Birding Magazine (October 2016)
BUBO is a listing website geared toward “friendly comparison” with other birders. About 3,500 birders worldwide use BUBO, tallying everything from world life lists to ABA year lists. An interesting aspect of BUBO is that you can view everyone else’s lists, poking around to find out where other birders are in their listing quests and gleaning tips on where to find coveted species.
Read the full "World Listing Software: An Abundance of Riches" article.