Including headlines in your sidebar is an old concept, one that can be very useful to both you and your readers. This post will by no means be a comprehensive list of methods, but I will outline what I feel are the ‘top 4’ ways to do this.

Peek-a-boo Headlines
Peek-a-boo headlines are a part of my version of FreshTags and may be coming to primary FreshTags eventually as well. I may soon be releasing a version of the hack that works well without a FreshTags installation. I really like this method because my blogroll still sends out link-love and for FreshTags users you get context-sensitive headlines.

FeedDigest
FeedDigest is an old friend of mine. The first-ever feed-to-script service I used was RSSDigest, the forerunner to FeedDigest. The service provides excellent features, including the ability to mix feeds together into a single digest, include scripts for JavaScript or PHP, and an RSS mashup feed of your digest. You get 100% code control over the output as well as the many prefab templates for newbies. The only problem here is that you can only run 5 digests — any more and you pay.

Feed-o-Style
Feed-o-Style is a newer cometitor to FeedDigest. You don’t get nearly the code control and there are no feed-mixing options, but their prefab templates are nice and customisable for most purposes. The only include option is JavaScript. There is also an ‘API’ by which you can generate feed-o-styles from a script.

Grazr
Grazr is a different sort of service. Their code is barely customisable and again the only include option is JavaScript, but that’s because the whole system runs using AJAX-style operation. Headlines from a feed can be included in your sidebar, or an entire OPML reading list can be rendered (XOXO not yet supported, see my sidebar for an example). ATOM feed support seems to be missing as of yet, and there are some other issues (mostly caused by the unreliability of implementations of the OPML ‘spec’) but overall it is a very interesting start.

There has been much discussion recently about comment syndication. I have made some of my own contributions to this, including Commentosphere and Blogger Recent Comments. While all of this is good and useful in its own way, syndication is useless without aggregation.

Currently, to track comments for interesting discussion / replies to your own you must subscribe to many comments feeds from different blogs and posts. This will quickly clutter your feedreader even if you only subscribe to the ones that are most important. Something that can help this, at least a little, is combining the feeds together into one megafeed, using something like feedshake or the Commentosphere Aggregator (see my aggregator for an example). While this works to some degree, it is ultimately unsatisfactory.

So here’s the idea — have feed readers aggregate comments alongside the post. A post then appears unread if it has unread comments as well as if it is itself unread. The new comments are highlighted on viewing the feed and marked unread. Another possibility would be to have a little ‘comments’ icon next to the post title that shows if there are no comments, new comments, or all read comments on a post. Clicking the icon would bring up the comments for that post (likely within the aggragator, not just a link to the #comments or anything like that).

This whole idea does, of course, assume that the aggregator can get to the comments somehow. There needs to be some way to take the link URL (usually to the post page) and get the comments feed URL for that post. (Assuming there is one. If there isn’t, that’s in the realm of syndication, not aggregation.) To facilitate this, I am proposing a simple piece of standard markup. Most blogs that have comments feeds for every post have a link to that feed somewhere on the post page. If we made it standard protocol to set rel=”alternate comments” (obviously, just like with relTag, you can have other things in the rel-list as well, but require both of these) for these links, the aggregators could pull them out of the page and get the appropriate URL. The aggregator could then get the comments feeds and use them to produce the features outlined above.