Meh, I really don't like the "Virtuous Cycle of Web Applications" [1]. It claims that retaining users amounts to doping them up every now and then with a "new functionality" to excite them and get them to use it again. Basically, feature spam.

This is a novelty approach, and it has no longevity. It doesn't last, and those aren't the users you want anyway. The webapps I use the most are the ones that actually offer something valuable to me. This sort of value is timeless. Google Docs is the first thing that comes to mind. I open Docs all the time on my own accord. Google don't whore themselves out with shiny new features because they don't have to. They wrote good software. It's a useful product.

I could see this strategy being more valid with web games, but as long as your webapp is a utility there's no dopamine burst you need provide users. Just help them get something accomplished and they'll be back.

[1] http://media.tumblr.com/600e20abfacc231409d9a715fd985b86/tum...