In the short term.. it means a good deal of propaganda.
In the long term, it depends. Osama was a charismatic leader that inspired a lot of people to open up their pocketbooks to the cause. The current second in command is irritating and obnoxious. If he does succeed OBL , then it is likely huge amount of resources, and support will disappear.
With OBL gone, there is the reasonable potential for the Taliban to distance themselves from al qaidia. If they do that, then for them to enter into peace talks with the government of Afghanistan is increased drastically.
Al qaidia had been billing itself as the only alternative to a lot of these brutal dictatorships in the Arab world. With the uprisings, and the lack of charismatic leadership , it is very possible that they will lose the support of much of the Arab world.
In the short term, it is a propaganda tool on both sides. In the long run, it all depends on who wins being the replacement for him.