So I had an email asking me HOW to program a search engine to find a coin, even a rare one. Let me start by saying... you can search for a coin with current search engines. My programming uses these current search engines to find what I want. HOWEVER..... because I'm lazy.... I use a Linux Server to do the job.... and it's a small system on my wireless network that does the searching for me.
Without getting into details..... my little server uses a --script to inject what I want and the results are emailed to me what it finds. I go to the server and redefine what I want to reduce the number of emails. It looks every hour on many sites, compares the search to a checklist from previous searches, sends an email of what it found new in the search, then adds the new item(s) to the checklist. Been doing this since 1990s (coins came later) and it works well. My -script has changed over the years as many of the search engines have "come and gone" or changed in the process.
The current system has worked well, especially as I learn more and found coins that are hidden in web crevices. Internet search engines are great tools.... if you know how to "abuse" them for a purpose