Why not just scrape the info from Wikipedia? It will be a lot easier for you to maintain, you'll have access to more data than you do now, and the information will be a lot more accurate. You can also fetch the latest info once a day (or more often for that matter) without worrying about your IP being blacklisted. Even if you had a million active users then I doubt you'd end up with more accurate and up-to-date info than what you can find on Wikipedia.
To me it also seems very misleading when countries that only allow 15-30 days visa-free entry are being listed as visa free. I like the layout of the website, but I personally can't see myself using it as long as I still need to visit Wikipedia for accurate information with regard to visa free duration.