Why?

Mydoom stopps spreading on Feb. 12. The SoBig worm did this too.
Anyone know why they do this?

creator did put end date to it or so…

:-X

maybe less likely to track down who wrote it?

not really sure

if they have a copy of the virus/worm they can still analyze it even after it stopps spreading

Mabye they plan on a new version of the worm or virus?