There’s Value In Stumbling
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.
How does one know what to submit to StumbleUpon? That’s content question for the ages. If it’s content worth talking about, it should be content worth submitting. Just don’t fall into the trap of submitting everything and often in the hopes that something sticks. Not only could that be construed spammy and abusive, it dilutes what good things you may have to offer.