As a community project, we have some advantages over others, some of which could also become disadvantages if we're not careful. Here's a quick primer on them.
The majority of our data come (note: data is plural, datum is singular, common mistake) from field surveys, meaning someone walks into an albergue, asks some questions, and then adds them to the database. This is semi-automated, a web app assists the field researcher in it. Note: We're always looking for more, if you're walking the Camino or planning on it, let us know.
The next most common way is the hospitaler@s themselves. Field researchers have the option to just pull up a QR code that allows hospitaler@s to browse to their personal editing interface themselves, and do it on their own systems. This is especially important when language barriers exist, since the hospitaler@ interface is internationalized.
We also send out occasional emails. Not as often, since we feel that this is the least personal way to map the Camino and antithetical to the Camino experience. However, some albergues close temporarily or change owners mid-way through the year, and then, or if we don't meet anyone there, an email can be sent.
Finally, there's Open Street Map, which is the world's biggest open GIS database. If all other things fail, that's where we turn. Funny side story: that's pretty much how most "Camino Apps" got their initial dataset, and often we find issues with OSM that we also see in those apps (such as wrong phone numbers or wrong number of beds). To make life better for everyone, we contribute our field research back (which OSM also requires for all things you get from then), and hope it propagates into other apps.