Good post, It is true that most of the influential people on twitter either have some software tweeting for them, or are paying someone to sit down all day and do it. The later is obviously much less cost effective. But I think you hit a good point that tweeting often is not enough. It's a the kind of spray gun attack we have come to frown upon by email marketers. Tweeting something important to your followers and keeping it simple, is far more effective than just tweeting. It only becomes really powerful when you combine the two.