I can't access data.gov. It says it's due to government funding. Is it down because of the US government shutdown and will be back or is it down for good?
Data.gov is down because of the US government shutdown. You can see almost identcal language on the census.gov website, which explains that the shutdown is causing the site to go offline.
Here is an article explaining more details about what is and is not available during the shutdown.
And if you are interested in seeing what APIs are available for when the website comes back online, try the Internet Archive for a list.
Data.gov was unavailable from October 1 through 16, 2013 due to the US Government shut down. This shut down affected the ability of agencies to provision and for the public to access a wide variety of government (.gov) web sites. As a result, Data.gov and the underlying data were not available. In most cases, the related agency site that could have served as an alternate path to government data (such as NASA.gov) were also unavailable for the same reason.
There are no long-term issues with the funding or viability of Data.gov. It is unfortunate that this shut down impacted the site, but it was not specific or unique to Data.gov or open data in the United States.
(Note: I am the Evangelist for Data.gov)