This is not the first time that Yahoo! has reached for its lawyers to target a firm about to go public. In 2004 it launched a legal assault on Google involving patents shortly before the search firm staged its own listing. Google ultimately agreed to a settlement over the matter, taking a $200m charge against its earnings to do so. Yahoo! is no doubt hoping that Facebook will throw in the towel as well to avoid awkward legal wrangling in the run-up to its initial public offering (IPO).

Perhaps Yahoo will patent the pre-IPO patent suit. A wonderful innovation that deserves state protection.