The money quote:
ProQuest Information and Learning and Allen County Public Library (Ft. Wayne, IN) add another milestone in their longstanding alliance with the release of a significant amount of new data in the Periodical Source Index (PERSI). With this update, PERSI now contains nearly 2 million citations from over 6,500 periodicals published in the United States, Canada, and abroad. The new release includes indexing for over 235,000 articles from 2004 and 2005. No other index covers periodical research in local history and genealogy as extensively as PERSI.
PERSI can be accessed at HeritageQuestOnline (through a subscribing library card) or at Ancestry.com. You can order copies of articles from the Allen County Public Library in Fort Wayne, Indiana.
I have used PERSI on occasion, and have found it helpful in finding periodical articles, especially concerning localities. There are many genealogy gems in these articles but they are very difficult to mine. Usually, you have to find an index for a specific periodical, or browse the periodical shelves at a genealogy library to find the gems. Some societies, such as New England HistGen Society, have indexed their periodical pages and made the images available, usually behind a membership firewall.
In order to make PERSI more useful to genealogists, there needs to be an every name index and images of the articles. This seems to me to be a very worthwhile project for companies like ProQuest or Ancestry. I think it would be a quantum leap in useful online genealogy data.
Heck, they've completed the census records - they must need new challenges! Are they listening?
UPDATE (9/29, 3:55 PM): It was pointed out to me that there might be copyright infringement issues for all post-1922 periodical issues and articles that would prevent digitizing of the periodicals in the PERSI collection. That makes the "worthwhile project" impossible to tackle. I was wishing and hoping...
An indexing project by the different societies or publishers, or by a subscription site, might be possible. Some journals, like the NEHG Register, already have published indexes, and I know there are quite a few others with published indexes.
My opinion is that the real "hidden gems" that many people strive to find are hiding in small circulation newsletters and journals in the Allen County library. A trip there might be in order.