Some people think differently on this subject and I am wondering how you all feel? Do you call your forum a "forum" or use an s and call it "forums"? Does this even matter to you at all?
But that's the whole point - if most people don't know it then if you require a pluralised form, "forums" would be better. If you do a Google.com search, you'll find there are 3,340,000,000 results for "forums" and only 175,000,000 results for "fora" (the first few results aren't even related to forums). You would want less confusion, ie. many large "forums" use "forums" as part of their domain or subdomain (Vogue, Whirlpool, DigitalPoint).
However, I don't think you're point about "forums" being "incorrect" is very valid. Both are acceptable and etymologists agree on both usages. In fact, the Latin word "forum" concerned a public square or marketplace, so it's not exactly what we today understanding as an Internet forum. Because meanings of words can fluctuate and change over time, one could argue "forums" is associated with its modern counterpart.