It uses the PostRank API, which looks like it has historical data for feeds that PostRank has previously analyzed. So maybe it can provide archived data for so

It uses the PostRank API, which looks like it has historical data for feeds that PostRank has previously analyzed. So maybe it can provide archived data for some feeds (but not all)? http://apidocs.postrank.com/Feed-Engagement-API http://apidocs.postrank.com/Feed-Engagement-API EDIT: For all the feeds I tried, it just started with the most recent item, not the first. So it's like having a DVR for feeds - you can time-shift them to watch later, but you can't go back and "record" things that happened in the past. I'd really like to create a similar service that crawls the site itself and uses heuristics to figure out the right order for all of the archived posts/entries.