Proxlet has been one of my more interesting projects. (It solves an acute Twitter pain, it allows you to mute noisy users/apps)
One thing I’ve learned is that on any given day, the usage/user-ratings for Proxlet very directly reflect the at-the-time quality of the Twitter API service. Twitter chokes up, folks perceive the middle-man-Proxlet as the issue, numbers go down. Twitter operates smoothly, Proxlet’s adoption continues to grow. (Not much we can do about that! Our quality of service is tied to Twitter’s! Unfortunately, that’s been fairly low as of late)
The second thing I’ve learned is that folks can be very demanding & critical of a free-service. It takes thick-skin to support those who assume your product wasn’t a labor of love, but rather the sole output of some full-time enterprise, and who criticize your execution accordingly. It’s worth reminding other developers out there: the noisy few don’t represent the thousands of silent, active, & satisfied users!