Don't know what software you are using but if it is outlook it might be working similar to my AOL. I know AOL gets it's browser from Internet Explorer. Maybe it's address book and email is similar to MS Products? Anyways there is a preference in my AOL that asks if I want AOL to save all the email addresses that I communicate with. If somone from here for instance sends me an off board reply to a post and I reply back they get put into my book. If I order something online the vendor gets put into my book. It is all automatic. I think it is called auto-enter or Auto-Add... or something like that. Buying from ebay I end up with a lot of names that I have to weed out from time to time. Maybe that is a source for a lot of names you don't recognize? It is good in that if you start a business relationship with someone or some company or start a new contact you automatically have a record of that contact in case you need to follow up. However it can get out of hand with the number of Auto-Add names of people that after maybe 4 or 5 days you may never need to contact them again but all their names are in your book. I just looked at my book and it is loaded with odd names. Some I don't recognize anymore. Fortunately, If I recall correctly, I can sort my addressbook for Auto-Add names and then isolate them for editing. I can then add info to them and change their status if I want to keep them. I have catagories (status) for, Train Watching or Ham Radio board members, Chip Collectors, Ebay, Friends, Family and so on. Then there is Auto-Add.

Like I said, I periodically go through. Sort out Auto-Add and sort through them and delete the ones that I have no use for.