Passive Voice Day 2012: "It has again been decided that April 27th will be passive voice day. Fun will be had by everybody as the passive voice is used for tweets, blogs, and casual conversation." (2011) Language Log offers kudos to a well-crafted passive announcement and provides further reading on confusion over avoiding the passive (includes a list of links to Language Log posts on the passive).
Language Log lists all their previous articles about prescriptivism vs. descriptivism (or at least a lot of them), plus a link to Geoffrey Pullum's Ideology, Power, and Linguistic Theory [pdf].
Although people have been worried about correct speech for thousands of years, it's apparently the status anxieties of modern societies that create the market for usage advice in which artificial "rules" can spring up and spread, independent of the genuine norms of speaking and writing. [via]