I think early on we were all just treating this as something of interest that we felt needed to be addressed, clarified, and fact-checked.
For the Wiki, my own goals were more to create a record of the issue (one of the better pages was a timeline of events). Wikipedia does this well today, particularly with large, long news events (look to the Boxing day and recent earthquake/tsunami): stories with many facets, in which facts emerge over time, etc. I find the Wiki treatment far superior to mainstream news outlets.
Blogs are more transactional, and I suspect more immediately rewarding of participation. Wikipedia itself took a number of years to really gather mass, but once it did it was unstoppable.
My sense was that there were far more people contributing to Groklaw. I believe we had a few score users, of whom a dozen or so were highly active. Among the amusing developments was when an account appeared under the name of Rob Enderle. I followed up on that as I was concerned someone might be spoofing him, but from all appearances it was legit.
No sour grapes either way, just one of my own observations. I'm interested in what tech works and what doesn't, as well as under what circumstances.