Update 2012-02-23: See a newer version of this article: How to Remove Yourself from www.Spoke.com and Center.Spoke.com.
Having a result on Spoke when searching for your name is a drag. In addition to their reputation for being spammy and intrusive, the data listed is often inaccurate or out of date. To remove your profile from such public searches, their FAQ provides the clue in the answer for My information in Spoke is wrong. How do I update it?:
… Go to www.spoke.com, search for your name, click your name to access your profile, then click the “This is me” button to update your profile and set privacy preferences. … If you would prefer to permanently suppress your information from Spoke’s directory, access your profile as described above, click the “This is me” button, select the “Learn more” link, then see instructions in the “How do I claim and update my Spoke Profile?” section.
After following these steps, my Spoke.com page still shows up in search results, but presumably that will stop at some point. In any case, anyone clicking on my profile will just see the message “This profile is no longer available”.
I recommend not installing their toolbar or providing any further information on the site. You should be able to give just enough to “claim” your profile, then disable the public view of it.