Update: A day after the fact, Delicious did issue a release acknowledging the separation from Yahoo! and stating “there is a ideal home for Delicious outside of the company.”

Social bookmarking service Del.icio.us – or, since the summer of 2008, plain old delicious.com – is officially on the way out after a corporate slideshow leaked yesterday depicted parent company Yahoo! deciding to “sunset” the product. And while there are plenty of other portable bookmarking services out there, Delicious’ longevity and the current backlash against Yahoo! in general meant that the social Internet went completely nuts over the news.

I can’t quite remember when I started using Delicious, but it was certainly before Yahoo! bought the service in 2005 (because I do remember it asking me to affiliate with my Yahoo! ID); as a consequence, I’ve got thousands of bookmarks stored in my personal account, not to mention the official World Company social media account. So, like scads of other folks involved in the collective Delicious freakout, I got a little antsy about preserving all that stuff we’d painstakingly bookmarked over the years.

Fortunately, yesterday afternoon’s panic settled down into today’s well-researched lists of Delicious alternatives (here’s a nice simple one) and endless Twitter tips about what’s best for which needs – because if there’s one thing to learn from all the chatter, it’s that the millions of people using Delicious have been using it in some pretty fundamentally different ways. Local tweep @ruralocity and a few others recommended Diigo over other big names, and after playing around with some services that just plain didn’t work and some services we wish did (Google Toolbar, looking at you here), it seems like a pretty good fit. If you’re keeping an eye on The World Company’s social-related bookmarks, you can find us on Diigo as worldcosocial … and if you’re not, we hope you will now.

So, pros and cons of Diigo?

Pro: Looks like it’s doing a good job of importing our existing Delicious bookmarks pretty seamlessly. (I’ll say looks like for now, since it’s kind of a painfully slow process; their servers have been understandably inundated with migration requests.)

Pro: Annotation (“sticky note”) and highlighting tools are great collaboration resources, once you get your preferences set – otherwise it’s a bit annoying to see some of your favorite high-traffic pages blanketed in little yellow stickies.

Pro: Nice add-on tools, including the choice between adding a full-on Diigo toolbar to your browser or a smaller, less intrusive bookmarklet that’s still pretty feature-rich. Javascript-based bookmarking for iPhone allows immediate tagging of new bookmarks, which is a huge relief after never quite being able to get the Delicious bookmarking on iPhone to work right. The offline reader app seems cool at first glance, too.

Pro: Good Twitter/Facebook sharing capabilities – enough maybe that I’m tempted to jettison my usual Shareaholic Firefox add-on.

Con: The Diigo toolbar, while immensely useful, takes up a huge amount of screen real estate; not so great on a laptop.

Con: No support for multiple accounts. To be fair, Delicious doesn’t do this either, but add-on apps like Pukka made working around this fairly easy.

Con: It sounds silly, maybe, but there’s no ctrl-B or ctrl-D keyboard replacement for bookmarking in the browser. If this morning has been any indication, this is by far the most annoying thing about the switch. (Good news: Diigo’s support forums are crawling with this complaint, so there’s hope for its inclusion sometime in the future.)

If you’re a Delicious user, are you already looking into replacements? What’s worked best for you? Let us know in the comments.