Ron’s answer covered the business context, content delivery, content creation, and the opportunities. Of particular interest to bloggers is content creation:
Blogs, podcasts, wikis, XML, and other new (web 2.0) technologies will affect content creation more than [content] delivery. Law firms have always generated a lot of content. Now, via blogs and RSS, they can distribute it more widely at low cost (see, e.g., the list of large firm blogs and RSS feeds). Government content is increasingly available over the web, with some agencies adding value over time (e.g., the SEC will add XBRML tags to EDGAR). Separately, low cost hardware and software platforms let niche content providers thrive. The growth of law firms, the government, and niche players as content providers could threaten publishers.
Ron’s right that “publishers can take advantage of new technologies to expand their delivery channels and customer base.”
However, legal publishers better realize right away that empowering legal bloggers with strong publishing platforms and distributing their content, without editing same and with value adds, yet to be determined (beyond just aggregation), is the business model that will bring the greatest growth.