I just saw today that there is a new option in Bloglines to keep a blog article as new.
Below every article, there is a "keep new" checkbox which will mark permanently the article as new. I find it handy when in the morning I quickly browse the weblogs and want to read more carefully some articles later. The problem with bloglines, it that once you've selected a blog, all the new articles are marked as read. Even if you haven't read all of them...
Bloglines already offered a similar feature for that (Clipping) but I find the user interface too tedious (to much clicks and setting) and the clipped article does not given enough hints about the weblog it belongs to.
This new checkbox solves partially one of the biggest disadvantage of Bloglines for me, the inability to mark articles of interest. It's great for temporary marking (e.g. for mail to read later in the day) but it's not very useful for "reference" articles since the display hints are the same for unread articles and articles marked as new.
For these reference articles, I still prefer to bookmark them in my del.icio.us bookmarks.