[snugs]

On the whole probably more introverts contribute to Internet forums than extroverts because it helps them express their viewpoint that they would have problems doing in a one to one or crowd situation. Also many have problems making friends so tend to use the Internet as a social tool as well.

This is of course again is a very over generalization but may account for some of the results.

Another category that also maybe involved in the web forum on a very regular basis is the one I would put myself in. Circumstances at home mean even if you would prefer to be out and about in the company of others you cannot because you have responsibilities at home.

[WFTR]

On the whole probably more introverts contribute to Internet forums than extroverts because it helps them express their viewpoint that they would have problems doing in a one to one or crowd situation. Also many have problems making friends so tend to use the Internet as a social tool as well.

This explanation sounds most plausible. The conservative extroverts are out doing non-political things with their friends instead of posting to a forum. When they are doing political things, they are at a political meeting somewhere.