Two things I missed when I moved from Firefox to Opera were the smart bookmarks which I had configured in Firefox to post to my delicious account and to subscribe to a feed using bloglines. It turns out Opera has custom buttons.
After finding the Del.Icio.Us custom buttons, I was able to make my own for bloglines.
s/bl <—drag this link to your Opera menu bar
Just drag this link into your menu. I like to name my s/bl for subscribe with bloglines. I like tiny abbreviations so that my menu doesn’t fill up.