Al-Shanfara is the spokesman for the group and, for me, his dual resignation is a worrying sign for Yemen's future. If people like al-Shanfara begin to feel as though they can't effect change through Parliament or through established political parties they will begin to associate more and more with the still nebulous southern movement.
This is not a direct parallel, but this is the same conclusion that Husayn Badr al-Din al-Huthi came to back in 1997 when he decided not to stand for re-election to parliament for Hizb al-Haqq.
The Southern Movement is much different than the Huthis, but as more and more people opt out of the political system the bigger the danger to Yemen's future stability. (Again, I had great plans for a long post - but the Yankees just wiggled out of a bases-loaded jam.)