In a post to the company's corporate privacy blog today, Comcast CEO Gerard Lewis promised to not sell their customers personal data. He went on to state "We do not sell our broadband customers’ individual web browsing history. We did not do it before the FCC’s rules were adopted, and we have no plans to do so."
Note the oddly specific use of language referring to "individual web browsing history". This does suggest that some data, presumably aggregated user data, is used for marketing purposes. As some were disappointed to find out after an attempt to counter this legislation by crowdfunding and buying the browsing data of members of congress, that's not quite how it works.
In other words, it seems there is nothing new to report here. Comcast won't be selling your individual browsing data, just like they weren't selling it before, but we still don't have a clear view of exactly what data they collect, how they aggregate it, what they do sell, and what security they have in place to protect that data. They are also asking their customers to trust that they do as they say, and won't change their minds down the road, which is a pretty large leap considering they are not virtually unregulated.