You in a lotta trouble, young man

>>So, one could be disfellowshipped for directly contradicting the Bible, but "dogma" has nothing to do with it.

The Governing Body (the "faithful and discreet slave") provides elders with a manual called "Pay Attention to Yourselves and to All the Flock". Despite the WatchTower organization's best efforts to keep this document secret (most importantly, from "the flock") by threats of copyright infringement lawsuits, it can now be found all over the net.

Here's a snippet you might be interested in:

"The Watchtower defines apostasy as "action taken against true worship of Jehovah or his established order among his dedicated people" (Pay Attention..., p. 94). This definition is significant: apostasy involves promoting religious teachings in opposition to the Watchtower and articulating any opinion that is critical of any action or position taken by the Society"

http://www.watchman.org/jw/1404-1.htm

>>I could not be disfellowshipped for "participating in this sort of discussion".

If the idea of being disfellowshipped bothers you, don't try the following experiment. Express to one of your elders that you have been discussing things with some folks on the internet, and have become confused by some of the arguments you have encountered. Ignore the admonitions I GUARANTEE he will give you (based on dogma like that found here: http://quotes.watchtower.ca/bewarethevoiceofstrangers.htm) to stop engaging in these discussions, go back again and tell him about that. Might take a few times.