When this forum goes over 40,000 posts, can you correct the grammar in the "header" at the same time as you update the number of posts? Yours, Mr. A. Nal (AKA SH)
The header says "this forum have....". It should say "this forum had....". Apologies from pedants corner.
It should now say "This forum has over 40,000 posts". Forum is an acceptable plural in this context. Fora is normally applied to the plural of physical places where folks gather to meet, mingle and discuss various issues.