Hi
No, I don't think the popularity of the F-16 has gone down. Just the popularity of the Forum and the Webmasters active participation in it.
Believe it or not Avitop.com is quite a busy site with several thousand daily visitors, but hardly anyone comes here because of the forum. Most people Visit Avitop.com because of the Aviation Top 100/1000 or to buy Aircraft.
Regards
Run - Webmaster Avitop.com