There are several ways of being able to find people like old work mates or old friends that you may have parted ways with in the past who you would like to get in touch with again. These days, the majority of people look for each other and stay in touch with one another through social media platforms such as Facebook and Twitter.
There are quite a few different social media platforms where you can interact with your existing and old friends and get in touch with those who you might not have been in touch with for a long time following your last meeting several years ago for example. If you are in such a situation looking for an old mate then make sure you get an account on one of the popular social media platforms especially Facebook or even Instagram as you will be able to quickly find people who may already have an account on this platform without much trouble.
If you're looking for Nicholas Trudeau and you have no idea what part of the world they might be in at present given that people have moved from different places to different parts of the world over the past decade or so then you can just try out names together with their surnames, that is, full names and if the names are unique then your chances of quickly identifying the right Nicholas would be improved. If you're aware of their location then you could further filter results by location by typing Nicholas Trudeau St. Augustine for example which would provide you with relevant details.