The Travel Advice Map (our Travel Advice Map profile) shows icons over countries that contain warnings from the UK's Foreign and Commonwealth Office. As such, it is meant for British citizens, but the advice likely applies to others.
Don't travel anywhere in Somalia, it says. Only go to Iran, Yemen and several other countries if it is essential. There are also partial warnings, where travel to one or more regions is discouraged.
The creator of the mashup, Mike Stenhouse, was unable to use an API to retrieve the data. Instead, he used a web page containing the warnings. The process of extracting data from a page is often called "screen scraping" and it is a questionable practice. Site owners sometimes intentionally do not provide an API because they don't want the data to be used outside of their own site.
In this situation, Stenhouse should be applauded. For one, he is using government data, so it should be openly available. The organization that collects the travel data would be wise to at least create an RSS feed of its warnings.
Also, this mashup shows the utility of open data and map visualization. Using screen scraping tools, such as Dapper (our Dapper API profile), to free data that should be open helps communicate the power of unleashing your own data. A mashup like this one is only one example of how developers often display and combine your information in ways you hadn't intended.