Thanks, Tess. This was helpful.
I went back and looked at it and it was a 'Web' Alert for my Services page, so I guess this means that for my search term (my company name), my services page appeared in the top twenty results of the Google Web Search.
It's probably just from my own clicking on the page when I was looking at it to reference something! Ha, ha.
In any case, I'm glad to have a better understanding of what it means when it comes up in my alerts.