What is the signifigance of a fillfactor of 20?

I have a database for our ticket system in SQL Server express. I was poking around and noticed that a lot of the indexes have a fillfactor set to 20. What is the signifigance of it being set to 20? Why would you set it so low?

@ 20 % you're consuming 5 times the disk actually needed for the index. I'm sure there's some business case where that might make sense, but I've never seen it. If you aren't rebuilding these regularly (rebuild returns to original fill factor level, in this case 20%), I'd be interested to see how full the indexes are after a month of operation. General ref: http://msdn.microsoft.com/en-us/library/ms177459.aspx

StackExchange Database Administrators Q#15496, answer score: 8