It's on pin 14, which is the master clock input (MCLK) of a WM8761: Low cost stereo DAC. I'm guessing it's meant to act as a small inductor? But why would you want that on a clock input?
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1\$\begingroup\$ Datasheet at wolfsonmicro.com/documents/uploads/data_sheets/en/WM8761.pdf \$\endgroup\$– Toby JaffeyCommented Aug 26, 2010 at 20:41
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3\$\begingroup\$ just to be clear, the trace does not form any sort of loop, and therefore has negligible inductance relative to a straight path between the components. \$\endgroup\$– SingleNegationEliminationCommented Aug 29, 2010 at 18:58
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16\$\begingroup\$ It's there to draw attention away from the two mistakenly-routed, yellow wires on the top of the board. \$\endgroup\$– Joel BCommented Feb 21, 2011 at 21:45
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It's a serpentine track. They are often used where equal track lengths are required with high-speed designs. In this case it is probably used to implement a very short delay.
answered Aug 26, 2010 at 20:38
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1\$\begingroup\$ They're everywhere on computer motherboards, because they use lots of high speed busses. Take a look! \$\endgroup\$ Commented Aug 26, 2010 at 20:58
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3\$\begingroup\$ 20 ms is 50 hz. I think you mean 20ns. \$\endgroup\$ Commented Aug 27, 2010 at 5:15
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2\$\begingroup\$ Apparently related terms: "skew minimization", "skew control", "serpentine delay", and you can do a trombone shape instead? \$\endgroup\$– endolithCommented Aug 27, 2010 at 14:11
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2\$\begingroup\$ @endolith, you can do other shapes, but you generally don't want the very beginning of the trace running too close to the very end, since they will couple together capacitively. \$\endgroup\$ Commented Aug 28, 2010 at 5:42
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1\$\begingroup\$ @ajs410: My guess would be that the device producing the data and clock for the device switches both simultaneously, and the squiggle helps ensure that the proper signal is registered first. Though that would seem an awfully short squiggle to have much effect. \$\endgroup\$– supercatCommented May 14, 2011 at 15:08