Until recently, D.C.'s laws were locked up. The city claims its laws are copyrighted, so the only way to actually know what laws say was to go to a library (hoping they had a physical copy of the code), pay almost $1000 to LexisNexis, or use a website that web advocates say is "awful."
Then Public.Resource.org bought the code, scanned it, and put it online, in a move hailed by online activists.
MediaShift covered the story and the why here
Importantly, what Public Resource did could be considered copyright violation, and it's still possible that either the District or LexisNexis could take legal action against the distribution of the city's laws. But when the laws of a city are available for its citizens to peruse, that can only be a good thing.