You are hitting on the right points but there may be a need here for more details related to investigative journalism. In the past, reporters were given more of a chance to spend more time on a story. In today’s world of deadline every minute and producing volumes of copy to feed the paper, site, syndication engines, there is more of an emphasis on getting the story out, and getting it out before one’s competitors.
In the process, investigation is dropped. As the deadline every minute frame of mind becomes more common, less time is spent on doing more research. If Watergate happened today, I fear that the story would end up getting buried and Woodward and Bernstein would be redeployed on other subjects. In a way, the Watergate scandal and the Trent Lott ouster parallel each others. A small, apparently insignificant event builds over the course of time and becomes a significant issue that eventually topples a powerful politician.
The only difference between the two is in who did the research. In the case of Watergate, the Washington Post editor gave its reporters enough leeway to investigate further. In the case of Trent Lott, a group of webloggers decided to do their own investigation and share the bits they had found. In a way, the Lott story could be a good example of collaborative journalism and could bring forth a rebirth of investigative journalism. Investigative journalism is time consuming, very costly (think of the output of an investigative reporter vs. a beat reporter) and can be risky from a legal standpoint (most investigative stories uncover things that people don’t want known).
On the other hand, collaborative journalism can spread the load. It allows for multiple people to build on research from previous people. I would not be surprised if, a few years from now, every serious newsroom has an internal blog with section broken out for bigger stories, allowing for multiple reporters to work jointly on stories.
Ultimately, blogging is about community, it’s about people sharing knowledge, and building on other people’s knowledge. This is why the Lott story happened. Someone posted a note about the original remark, a reader remember another fact related to the story and contributed it to the conversation. That triggered an answer by a third person, and so on and so forth. Because bloggers are passionate about what they are doing, they provide heavy background in the form of links to actual sources, making it more and more difficult for anyone to hide in plain sight.