I often sign up because something seems neat, or because it solves a problem I know I have.

It would be great if the 30 day trial started the first time I really start using the software.

A great alternative is for a company to offer a newsletter. Then I can get reminders about what they do, learn about how great they are, and sign up when I'm ready to use the software.

I'm bad at estimating time frames. I often think I need something (e.g., KissMetrics) next week. In reality, I won't start using it for months.