I did setup a bookmarklet to use the Update.bml page of Livejournal.

It grabs the title of the web page, the selected text, and generates a link back to the web page:

javascript:d=document;t=d.selection?d.selection.createRange().text:d.getSelection();void(window.open('http://www.livejournal.com/update.bml?mode=full&event='+escape(d.title)+escape('\n\n<I>')+escape(t)+escape('</I>\n\n')+'<a href"'+escape('=')+escape(d.location.href)+'">Goto Website</a>'))

In Opera, go to your bookmarks and select "New Bookmark", give it a name(I called mine "LJ This!"), a nickname("lj), and for the url paste the above code.

Now if you click on the bookmark when you have a page open it will open the LJ entry page and paste your text.

Alternately, you can simply type the nickname in the address bar and it will do the same.

If your like me though, that isn't good enough. So the next thing I did is go to the preferences page, go over to Keyboard and Mouse preferences. Double click on your currently active settings(probably Opera Standard). Expand "Applications" and click on "New". For the shortcut, give it an unused key/ctrl/shift combo(I used l ctrl shf which is their way of saying hold down the control shift and l keys). For the action, choose: Go to nickname, "lj" - where you put your nickname in place of lj if you decided on a different one.

So, now you can do a simple swipe text and CTRL-SHIFT-L and launch the blog editor.

For real fun, you can copy over the standard_menu.ini file to your own custom menu.ini file and add a link to the document menu so you can have a Right Click-->LJ This! option which invokes the nickname as well.