Facebook and its mildly retarded cousin Twitter have unleashed a huge demand for pithy remarks, single sentences so clever and incisive that they are instantly echoed around the globe. If one's worth is measured by the number of followers one has, then the exponent of that worth is the number of one's pithy messages that get re-Tweeted. Alas, the supply of cleverness has not kept pace with the demand.
Maybe this accounts for the proliferation of the phrases "Go figure" and "Just sayin'." If a tweeted observation seems particularly banal, just add the ironic eye-roll "go figure" and you've got the sophisticated air of one who's seen everything. "Just sayin'" works much the same way: It implies an amused exasperation with this absurd world, a touch of whimsy that is not immediately apparent in the trite thought that preceeds it.
If those don't work, there are always the "LOL!" "OMG" and "Snort!" These handy interjections -- employed in front of the re-Tweeted or linked item, not after -- show that your discerning eye has discovered something incredibly amusing. Almost as amusing as if you'd thought of it yourself.