---> However, the search functionality doesn't seem to retrieve information previous to the new site.
That is mostly correct with a few exceptions.
The articles in the old site software are in a radically different format from the new site so there is no automated method of copying from the old to the new. Instead, I am manually cutting-and-pasting articles as time allows. I copied several this past weekend.
HOWEVER, I am finding that many of the old articles are either out-of-date or no longer relevant. For instance, an article I posed in 2006 describing the planned agenda for an "upcoming" genealogy conference to be held in 2007doesn't have much value now. I am not copying messages about "future" events that occurred years ago.
Also, an amazing number of articles are for out-of-date products, URLs that have changed, companies that are no longer in business, and so on. I will not be copying those. Also, checking URLs and finding updated addresses is often a very slow process so the process of manually posting articles will require months to complete.