The rise of link sharing on Twitter has cut down on many peoples' use of RSS readers and social bookmarking services like Delicious. Now blog post ranking service PostRank is aiming to systematize that shift - and they've done a really good job.

Imagine a system for delivering only high-value information via Twitter. That's what PostRank has built with its new PostRank Twitter Newsroom. The system finds the most engaging blogs on various topics, then automatically pulls the most talked-about posts from those blogs and now delivers those links to you via Twitter.

Trust us, we're as tired as you are of blog posts about Twitter - but these kinds of developments on top of the platform keep us coming back, day after day. Twitter is incredibly sticky for users and has a great API - thus it's captured so many imaginations.

We're big fans of PostRank here at ReadWriteWeb. The service takes inbound RSS feeds and scores each item in those feeds by number of comments, inbound links, mentions on Twitter, saves in Delicious, votes on Digg and other feedback metrics. It then allows you to subscribe to the 10% of the items in any feed that are most popular with that blog's own community of readers. It's an awesome way to keep track of the break-out hits on any topic, from any source.

Now PostRank has taken the next step and discovered the blogs about various topics that are most "engaging" with their own readers. For 50 topics at launch and more in the future, the PostRank Newsroom now aggregates the most talked about posts on the most engaging topical blogs and delivers them to subscribers on Twitter.

Want to get the hottest posts from the top blogs in law, marketing, music, nonprofits or programming in Ruby sent to you by Twitter? Now you can. That's a valuable service.

The editorial selection to determine which blogs are in which categories is open to question. We're not sure why we're in Entrepreneurship, for example, and not startups or tech. And we're not sure that the full Digg front page feed is suitable for the Mac category - but hopefully these things will get worked out with reader feedback.

It's similar to something we did last year for the DEMO event, where instead of racing a bunch of other blogs to cover all the startups at DEMO we grabbed their RSS feeds, filtered for the word DEMO, ran them through PostRank and then put that feed into a Twitter account that people could subscribe to. It worked pretty well, so we expect this new implementation from the company will work as well or better.

In this case the links are published from well explained Twitter accounts, with hashtags. We expect people will retweet them and it will be a great way to spread the word about PostRank.

Twitter for high-value information? It might be hard for some people to believe - but this kind of machine processing to add value to people-published content is exactly the kind of development we expect to define the next phase of the web.

You can find ReadWriteWeb on Twitter, as well as the entire RWW Team: Marshall Kirkpatrick, Bernard Lunn, Alex Iskold, Sarah Perez, Frederic Lardinois, Rick Turoczy, Sean Ammirati, Lidija Davis and Phil Glockner.