I like routines and that is especially true when it comes to my Web/Internet activities.
I go to the same 10-15 sites/services a day. I have habits around my laptop usage (Gmail, Twitter, Facebook, CNN, etc), my home computer usage (add Weather and learning sites), my iPhone usage (NYT, Facebook, Twitter, Text, etc), my iPad usage, etc. So I almost engage mindlessly at times, without thinking. Sometimes I'll just pull up CNN for no particular reason and then wonder, why did I do that?
I think I'm pretty typical of heavy tech users. Our fingers do the walking to our usual stops. So the challenge is how to break and enter that routine. This applies to Software as a Service businesses, online communities, wiki/info sites, and has relevancy for any Website. One visit is nice but routine, daily use is the real deal.
I think about this in terms of our Content Management System. How do I get my clients to make that a regular stop? How do breaking into their routine?
Increasingly I think the most effective way is to enter via a side door, an existing routine. I'm writing this blog via my Gmail account. I send it as an email to Posterous, then it is automatically posted to my www.jebbanner.com blog. They have found an effective way to enter my routine. Otherwise I doubt I would post half as often as I do. It may only be a couple clicks to get to their system but that seems huge in my mind.
In my comfortable email environment I can type away without worrying whether the post will be accepted when I hit submit or what the formatting rules are. I am more likely to engage when I am comfortable. Consider how to apply that to anything you build. Where are your target users living? How far can you go to break and enter their routine without them leaving their comfort zone? Focus on those solutions over fancy bells and whistles within the app or site itself.