Both AVN and XBiz rely on outsiders to their organizations to suggest nominations. It is entirely possible that you have industry employed fans suggesting your website as wonderful and amazing, then folks at either organization making it happen based on subject matter experts who ARE members of your website. I don't vote in the web based stuff nor do I generally nominate things in areas outside my areas of expertise so that is perhaps the best answer I can provide you.

For all I know, they needed one more website and having received several pre-noms for it, they vetted the site by reading reviews. As far as the winning website, if it had been updated "within the last six months" then it surely fell into the time table of awards for either group for when it was updated, those who may have loved it earlier in the year picking it over a more frequently updated site. (If you joined after the nomination period, it would have had a full year to be seen by whomever votes).

In some categories, there are very few voters who therefore hold more sway. Most feel competent voting for best performer even if they have only seen a few performances per each nominee, in other categories, there might only be a few subject matter experts such as tranny, BBW, gay, or whatever.