Absolutely, it's amazing. In my experience, it usually arises in one of three scenarios:
1) It's a halfway-legitimate indignance on Mongo's part as someone sees a simple tweet or other paltry report about a recruit and asks "why the hell haven't we seen anything about this guy here?" Mongo sometimes has done just that update, and very recently, so he comes in with this reply. Fair enough there.
2) Another source, usually but not always 247, breaks a new story of some import on a recruit. This information gets brought to the Scrolls, and excitement ensues. In response to either an implicit or explicit feeling that HOL is getting its lunch eaten by 247 (it usually is on recruiting stories), Mongo shuffles into the thread and raises the update he had on that recruit. Unfortunately, as you mention above, it's stale and doesn't really have much to do with the important information that's been broken by the other outlet. Still, Mongo feels like he planted his flag there months back, so that's worth something.
3) This is my favorite of them: Steve Wiltfong or someone else respected logs a CB for a recruit either in favor of Nebraska or moves off the Huskers to another school. There are now examples of both where Mongo has made that same prediction earlier without close to the fanfare. When he brings this up, the response is often "Well, okay, but we were waiting for someone credible to make this prediction before we got too excited." It's so damning, yet so funny.