If I were an agency of shills tasked with co-opting the 9/11 Truth Movement on the web...

for the purpose of slowing down the progress of the truth movement and protecting key perpetrators from exposure, what strategies/weapons would I employ?

First of all, some of the goals would be:

1) Attempt to discredit the best evidence, while putting out false bread crumb trails to the group(s) we want to frame.
1a) I would target and disrupt/discredit the evidence that puts the perpetrators most at risk of exposure
1b) I would target and disrupt/discredit those activists who attempt to bring up this evidence
1c) I would try to mold the web into a gatekeeping function to catch new 9/11 activists and divert them away from the best evidence.

I think I would do some of the following:

1) Gain credibility among activists by pretending that I am a real 9/11 truth activist by stating that I agree that 9/11 was an "inside job" and claiming that I am interesting in finding out the truth and identifying the real perpetrators. A great conditioning tactic would be to befriend the favored victims - the family members of the victims in NYC and get them on my side - it's a GREAT EMOTIONAL CLUB to use against detractors
2) Create "9/11 truth" web sites that divert people to what I want them to believe, and to only look at the evidence I want them to look at.
3) Attempt to co-opt pre-existing 9/11 truth web sites by gaining the trust and confidence of the current owners/moderators, and eventually get into the position of being a moderator/censor myself.

The most important tactic to successfully sway opinion on the web would be the use of Artificial Consensus

This can be very effective against the inevitable dissenters who will notice that I am promoting unpopular theories that do not reflect the majority opinion of the real truth movement. For example, If I can control most of the important and popular 9/11 web sites, using approximately a dozen agents posing as 9/11 truth activists some of whom are moderators/censors, and the rest who are posing as active bloggers, we can create an artificial False Consensus and completely dominate the online discussions regarding:

A) The Controlled Demolition evidence: Claim that it is "speculative" and is only used to "make us look bad", etc. Even though at least 99.9% of seasoned 9/11 truthers don't believe this, we can turn reality upside down and make it look like the majority of truthers do NOT accept the CD evidence as proven. Of course, we will have to eventually employ censorship and banning to keep this false consensus going for very long. It's amazing, though, what can be accomplished with about a dozen shills dominating the most important web sites, along with a dozen or more dupes, like comic book authority types who are desperate to be on the "winning team". Makes me chuckle...you can find these dupes and idiots everywhere

B) The no Boeing at the Pentagon evidence: Claim that only "disinfo" agents promote such "nonsense" and again make it look like most 9/11 activists are on our side by dominating the discussion as in A above. Cross referencing articles between 911truth.org, wtc7.net, truthmove.org, 911blogger.com, oilempire.us, and as many other sites we can control will make it appear that all "respectable" 9/11 truth "researchers" reject the no Boeing theory.

Well, I could keep going, but I'm out of time. Feel free to add to this.

Good to remind ourselves that the web version of 9/11 truth does not contain more than a very small part of the "9/11 truth movement", and the Real movement is in the Real world...