The OP raises a pretty thought-provoking question about traffic numbers. Logic dictates that it would depend on a variety of factors such as the specific site niche, the age of the blog or website, and how much effort the owner puts into promotion. Newbie site authors can also face uncertainty and plenty of information bombardment about the best ways to increase traffic. As plenty of members here can probably attest, some methods and services are great for building traffic while others are lackluster at best. The question of what constitutes good traffic is a good starting point for setting goals, and this step is also where some niche site comparison is worth the time. What equals great traffic for one niche can equal poor traffic for the next, even though the numbers are exactly the same.