Both LinkedIn and Twitter have been rolling out "enhancements" to their interfaces to make them look, feel, and behave more like Facebook. I'm already suffering from information overload, so giving me even more places to look for and access even more information than I already have seems to me to be more like a bug than a feature. And Facebook fails utterly at coherent interface design, so the mad rush to be "just like Facebook" really is a bug, not a feature.