Idea for Blogger

For an ordinary blogger like me, the spam comments seems to come mostly with a delay of at least a few weeks (presumably after the spambots have decided which posts to spam), whereas most of the legitimate comments come within a few days. I’d rather not subject legitimate commenters to those annoying human-readable text tests if I don’t have to. Here’s my suggestion: Blogger should have a time delay (chosen by the blogger) before applying the test. So if you comment within, say, the first 3 days, your comment will go straight through, whereas if you comment a month later, you’ll be subject to a security check. (Or do they already have this feature, and I don’t know about it?)