Taipei MRT Ridership in 2012

2012's top ten stations are listed below, ranked by the number of times each station was entered and exited.

Station	Line	Exits+Entrances
Taipei Main Station	Red, Blue	114,659,000
Taipei City Hall	Blue	45,723,000
Ximen	Blue, Xiaonanmen	41,935,000
Zhongxiao Fuxing	Blue, Brown	37,751,000
Zhongxiao Dunhua	Blue	28,972,000
Danshui	Red	27,884,000
Xinpu	Blue	26,980,000
Jiantan	Red	25,293,000
Banqiao	Blue	24,531,000
Zhongshan	Red	22,971,000

The most noteworthy change from last year is Xinpu's drop from 5th place to 7th place, presumably because some of the people from Xinzhuang who used to transfer to the MRT there now instead can use the Xinzhuang Line.  Banqiao also moved up a place, overtaking Zhongshan.  No station opened after 2006 has yet entered the top 10.
The least-used stations in 2012 are as follows:

Station	Line	Exits+Entrances
Nangang Software Park	Brown	687,000
Xiaobitan	Xiaobitan	1,217,000
Wanfang Community	Brown	1,372,000
Xianse Temple	Orange	1,778,000
Sanchong	Orange	1,809,000
Dahu Park	Brown	1,842,000
Zhongyi	Red	2,047,000
Xinhai	Brown	2,065,000
Fuxinggang	Red	2,462,000
Touqianzhuang	Orange	2,539,000

As should be expected, many Muzha-Neihu line stations are among the bottom ten.  The Muzha-Neihu line is lower capacity than the other lines, with no station other than Zhongxiao Fuxing even approaching 20 million entrances and exits every year, but with trains and stations being crowded regardless, so this is to be expected.  More disappointing (though not surprising, as I will explain below) is the presence of three stations on the high-capacity Xinzhuang Line.
Below is the ridership of the average station on each line:

Blue:                                      20,283
Danshui/ Zhonghe/ Xindian:    13,592
Xinzhuang (incl Luzhou):         6,153
Brown:                                   5,828

And the ridership for separate branches:

Danshui:                                 14,721
Xindian:                                   9,660
Zhonghe:                                 15,665
Xinzhuang (Xinbei section):       4,377
Luzhou:                                   6,598

The blue line has much denser usage than any other line, while the Xinzhuang Line has the least-dense usage, even less than the lower-capacity Wenhu Line.  This confirms what the list of least-used stations suggests: the Xinzhuang Line is very underused compared to other lines.  Presumably its ridership will grow a little more as more people try it or move to Xinzhuang with the intention of using it, and as new lines increase the usefulness of the system as a whole.  But even if it does grow, this is a very low point to start from.
The Xinzhuang Line passes through very dense areas that should have plenty of demand for an MRT line into Taipei City, so why is it faring so poorly?  A major issue is probably its route.  Rather than taking a direct path from Xinzhuang and south Sanchong into Taipei, the line makes a long detour north to join the Luzhou Line and enter Taipei under the Taipei Bridge.  While this looks elegant on a road map, it forces riders to take a roundabout route to get to most of the rest of the MRT system, especially the blue line.  This means that many Xinzhuang residents may find that taking the bus or driving is actually faster than taking the MRT, and that those who do choose to take it will be forced to spend more time in transit.  If the Xinzhuang Line had been built so that it crossed into Taipei under the Zhongxiao Bridge or the Zhongxing Bridge we would certainly see much greater ridership on the Xinzhuang Line, and therefore in the MRT system as a whole.  On the other hand, the Luzhou Branch has a much more direct route into Taipei, but also has low ridership compared to other branch lines, so perhaps the scooter-oriented nature of urban development west of the Danshui River is to blame.