Does this mean that you're inferring that Kialo.com has more than 11,000 public debates because it is better? In order for this support to work you'd have to add another premise that goes something like, "Kialo.com must be better than Internet Argument in facilitating huge discussion because it has 11,000 public debates and Internet Argument has very few." It seems like you could instead make this support a lot stronger by leaving out this premise, because it's hard to connect it to the topic statement.

It seems like this doesn't challenge whether the topic statement is true, but whether it matters. It could be a challenge to another statement that you consider to be more relevant, such as, "It is better to use Kialo.com than Internet Argument." which implies more that there's no reason at all to use Internet Argument.