Built In Preview
It is all very well users creating special scripts for Firefox which very few people know about, but ultimately the most useful interface features are much better if they are made available by default for all users to enjoy. Even the Google Reader Greasemonkey script has only been installed 11,000 times despite Google Reader having millions of users, even if you allow for people installing a script multiple times.
That is why I am glad that Bloglines have now added this feature as a default option within their 3 panel view, and I hope they find a way to add it to all views.
After you click the preview button, a full view of the site opens in the pane
This might lead to a few more advertising impressions and page views, but hopefully it will also lead to more interaction with blog readership. I am sure this will be very useful for those sites that still insist on publishing partial feeds.