Check out the Alexa graph here.
First guess that comes to mind is that they started removing all the porn :) Anyone know for sure??
UPDATE: Crazy. After some research, I found this on Wikipedia..
TextAmerica recently (January 1, 2007) went all-pay, as they had announced they would do in the past (see links below). All the moblogs and content from free users who did not choose to pay the $99 fee were removed. Oddly, the $99 fee was described only as keeping the moblog paid for available until November 2007, with no mention of what would happen at that time.
Pretty amazing that while everyone and their mother goes to an free with advertising model to gain big traffic numbers and big valuations, TextAmerica goes the other way. There’s probably a big hole in the market left after this – I spent some more time looking for other moblogging sites and there doesn’t seem to be a close competitor.