This graph shows how often people searched for "Real IRA" or "Continuity IRA" on Google, as a proportion of total Google searches, since 2004:
For the Real IRA, searches are steadily falling from 2004 to 2009. The Continuity IRA attracts fewer searches.
But both show a steep increase in searches in 2009 - just as the Real IRA killed two British soldiers and the Continuity IRA killed a police officer. Both groups then quickly return to low search levels.
So what does this mean? These groups seem to be able to maintain interest and attention through violence. Without successful violence, the public rapidly loses interest, however. If they want to raise their profiles in the long term they may need to keep killing.
(Of course many people searching for them during this period of post-killing excitement may be opposed to them, but I assume they do want publicity one way or another.)
It is a little disturbing and sad to realise that violence probably does benefit these organisations by projecting them into the media and, from there, into the curiosity of the public.