That is a shame that your valuable posts went poof, Perhaps you are not aware - this had to do with a change of ownership of the Frommer's forums, not a forum style change, per se.
Google bought the Frommer's brand from John Wiley and Sons. A few months ago, Frommer's bought the brand back from Google. However, in that handover, much of the content of the website was lost.
The Frommer's staff and a number of the regular contributors have been working to resurrect some of the old threads while getting the new site up and running.
If you happen to have copies of any of your old stuff, consider reposting it as trip reports or articles. If you have anything saved from others that you think would be valuable for resurrect, repost it with credit.