One of the things that turns plain applications into social applicationsis the ability to get feedback from other people ,the ability to know that other people are appreciating your stuff. Ithink it follows as a corollary that if you want to build a popularsocial application, getting the feedback right matters a lot; the morefeedback people get, the more likely they are to continue using yoursocial application.

To be specific for a bit, let's talk about Flickr (partly because I haveexperience with it as a

I have recently run into an interesting collision between typicalweb analytics practices (and applying this to random URLs) and goodsecurity and robustness. The straightforward manifestation is that linksto WanderingThoughts entries from the Planet Sysadmin Twitter feed don't work; trying to follow one getsyou remarkably terse error messages from DWiki (the software behind WanderingThoughts ).

DWiki is very cautious. One of the ways that this manifests is that itdoesn't accept random query parameters on requests; it knows what queryparameters each URL accepts,