StumbleUpon has launched a new advertising system, which the company says helps cost-effectively deliver advertiser content to targeted audiences, while increasing the opportunity for content to go viral.

Today is, for better or for worse, the last day many people will have off before heading back to work or school and resuming normal life.  And if you have lots of stuff to do, good luck.  But if you’re a bit bored – maybe still stuck at a relative’s house or just out of books to read – here are some of the "Most Stumbled Sites of 2009."

Earlier this month, StumbleUpon started showcasing their new homepage design, when they touted their “Google + Twitter” social search. Now they’ve gone through the rest of the site to make it more consistent (less customizable), easy to understand and streamlined.

Update: Starting today, all StumbleUpon users can access the new interface, according to the company.

Original Article: StubmleUpon launched a big redesign today. The new version of the site comes with a variety of new features, which the company says are designed to make it simpler, searchable, and more social.

A while back, StumbleUpon launched web stumbling, which allowed users to enjoy their StumbleUpon experience without having to download the toolbar, which was previously a requirement. If you’ve been a user of the service for a significant length of time, you’ve probably grown quite accustomed to that toolbar. Sometimes I forget it’s not just part of Firefox.

Facebook and Twitter have both been proven to be valuable sources of traffic to many sites, but another potential source that you might be overlooking is StumbleUpon. It is true that in the past, StumbleUpon has been presented as a traffic tool, but the results weren’t always what webmasters and marketers had hoped for.

StumleUpon announced today that it has launched a new URL-shortening service called Su.pr. The twist, however, is that this one is designed to help content creators actually increase their traffic with it. According to StumbleUpon, this is the first such service that does this.

A while back, StumbleUpon released web stumbling, which is the ability to use the service without having to download the toolbar that has accompanied it for years. The company has now announced some features that expand upon this. The StumbleUpon Team shares them with WebProNews:

First there were the acquisition rumors, then the acquisition. Then there were the sale rumors.

StumbleUpon is no longer part of eBay. Many have wondered why it was even part of it to begin with, but that pondering can now be put aside. The company has now been returned to its creators for an undisclosed amount.

The United States Marines, the Mormon Church, and the Korean Department of Tourism are all paying Australian-based uSocial to game Digg.com for them, according to a blog post at the Los Angeles Times.

Twitterer Veronica Belmont had discovered a Flickr page with an alleged upcoming toolbar from Digg that would potentially rival StumbleUpon.

I fired some questions at StumbleUpon’s VP of Business Development, John Bryan. We talked about StumbleUpon advertising, the future of social advertising and more. I even tried to get him to spill a few beans about eBay’s interest in selling StumbleUpon. Here it goes…

Chris Crum: What is the benefit to an advertiser to spend money advertising with StumbleUpon as opposed to simply submitting their site like anyone else?

Among all the social media tools that are available to companies, blogs top the list when it comes to lead generation according to a new survey from HubSpot.

The survey "The State of Inbound Marketing" asked 167 executives and business owners about their marketing strategies.

There is an interesting article at Seeking Alpha called "Why ‘GooBay’ Makes Sense." Obviously this is a "what if Google bought eBay?" piece, and feedback to the article thus far isn’t real keen on the idea, but there are some valid points throughout the article nevertheless.

StumbleUpon announced today that it will be rolling out a new design to make the service more accessible to new users. The biggest drawback has always been the fact that users had to install a toolbar to use the service, but with this new design, the need to do so has been eliminated.

TechCrunch is reporting eBay is trying to unload StumbleUpon, citing "sources with knowledge of the sale process." eBay is apparently using Deutsche Bank to find a suitable buyer, and the asking price has not been disclosed.

ProBlogger enjoyed significant traffic from bookmarking site StumbleUpon, until the site declared ProBlogger unwelcome at its domain; thanks to social media, that changed fast.

The StumbleVideos section of StumbleUpon gained in content with the addition of several new content partners.

StumbleUpon has been around a while, and if you’re like 5 million others, you understand what an addictive, stimulus-response type network it really is. But like with other social networks such as Digg, Twitter, or Facebook, many marketers are still at a loss for how to make the most of it.

Here’s an interesting question put forth by webmasters: What’s a link in StumbleUpon worth? Well, it’s nofollowed, which means not much in terms of link juice. But there may be an indirect value.

Part of that, of course, is branding. It’s good to be found in as many places as possible. But another value, as noted at SearchEngineRoundtable, is the chance that somebody stumbles upon your site and blogs about it. If so, you’ve just earned another endorsement and possibly a good link.