1. Because the popular industries are where most of the jobs / money are.
2. Because software by itself isn't going to solve most of the other problems you listed.
We're also trying to find the "hook" that would make such a site more useful to newsletter readers.
For individual articles, do you find sites like Hacker News or Reddit good for that purpose? I think there are certain authors whose writing is consistently good, and those are the ones we're trying to identify -- curious what you think.
We started Webletters to solve a problem: how do we find quality publishers and writers on the Internet?
We love to read. Sites like Hackernews are great for surfacing individual links and stories, but it's hard to find consistently awesome sources beyond word-of-mouth and what's currently popular. Ratings and reviews are our solution: by aggregating comments in one place, we have a more reliable signal on which bloggers and writers are worth following.
At Webletters, we're compiling online newsletters and blogs so that you can review, share, and discover your favorites. The quality of our database is driven by the users. Please contribute your favorites, and write them a review!