Below is a simple bookmarklet that can be used to toggle long posts on planet.debian.org(p.d.o). Erich Schubert had given the idea about how to "fold" p.d.o entries. And then Daniel Silverstone gave a quick hack for Firefox users in shape of a style rule for your userContent.css. And as Erich wanted a javascript to un-limit blog postings size, here is one called "pdoFoldToggle".
Bookmarklet pdoFoldToggle does not only fold long entries (longer than 30em height) but also unfolds. So basically it is a toggle for folding entries longer than 30em. Whereas the userContent.css approach is elegant, it does not allow you to toggle the entries. pdoFoldToggle allows you to toggle feature for long entries but the drawback is that you have to manually activate the toggle action. So its your choice which method you use to "fold" (urghh..) the entries. For using pdoFoldToggle, read instructions below. A combined approach is a good idea ... stay tuned for another bookmarklet ;)
Installation: You can just drag the bookmarklet button(not really a button, but a simulated one) to your Firefox bookmarks toolbar. When you visit p.d.o, use the bookmarklet to toggle between folded and unfolded entries.
To configure the pdoFoldToggle bookmarklet to a different height(default is 30em), edit the bookmark after dragging it to your Personal Bookmarks folder. Changing the variable maxH will change the allowed max-height for the entries.
This bookmarklet works in conjunction with Daniel's userContent.css hack. With the rules for userContent.css set, folding takes place by default. But in case you want to read a long post and don't want those scrollbars just for reading it, use the pdoUnfold bookmarklet to unfold the entries.
Install the same way as done for pdoFoldToggle.
PS: this was my first ever attempt to write some javascript using DOM. So please excuse if there are some errors.