Surprise, suprise... not one but two studies find no effects (positive or negative) from "compression garments." Now naturally, some may argue that positive effects do exist but that the authors of the studies did not attempt to measure them. However, until I see data, I remain a skeptic. Also, the blog post fails to mention one definite benefit: the ability of long socks to significantly decrease convective cooling on cold days.
In all honesty though, I really just liked the article because of this quote, which I think is particularly applicable to triathletes: "In light of the findings, Laymon speculates that the popularity of the garments reflects their trendiness, not their ability to enhance performance."