From the announcement blog post:<p><i>Transit is self describing using tags, and encourages transmitting information using maps, which have named keys&#x2F;fields which will repeat often in data. These overheads, typical of self-describing formats, are mitigated in Transit by an integrated cache code system, which replaces repetitive data with small codes. This yields not only a reduction in size, but also an increase in performance and memory utilization. Contrast this with gzipping, which, while it may reduce size on the wire, takes time and doesn&#x27;t reduce the amount of text to be parsed or the number of objects generated in memory after parsing.</i><p>- <a href="http:&#x2F;&#x2F;blog.cognitect.com&#x2F;blog&#x2F;2014&#x2F;7&#x2F;22&#x2F;transit" rel="nofollow">http:&#x2F;&#x2F;blog.cognitect.com&#x2F;blog&#x2F;2014&#x2F;7&#x2F;22&#x2F;transit</a>