Eighty Percent Solution
From this post on Statistics for Google Gadgets:
It's very interesting to note that 44% of the total number of page views were for the 28 gadgets created by Google.Google has this eighty percent solution thing down. (Well, in this case 44%--but you know what I mean.) They build just enough functionality to satisfy a large number of people, they release said software, and they improve incrementally.