Hi David,
I was introduced to pre-wwii cards at a very early age by those Dover reprint books. I've posted that before and a few people in my age group (30ish) PM'd me to share their version of the same story.
Today, I believe it's Topps that has taken on this role. A lot of us here have mixed feeling's about these 'chase' cards inserted into modern products, many featuring items mangled game used items. The most popular items in terms of value seem to be of players like Babe Ruth and Lou Gehrig.
They've also released products like Topps 206 where the cards look like t206 and they also randomly insert t206s into the product. I know there are a few board members that got into vintage this way.
Here is a cool thread with a poll outlining the general age groups of those who participated:
http://www.net54baseball.com/showthr...light=age+poll