I recently added a ShareThis link 
to each of my posts. I chose ShareThis.com because it seems to be very robust while leaving a relatively small footprint on the blog and appears relatively unintrusiveness and benign. Of course, some folks will be quick to point out that the tracking features and having the icon linked back to sharethis.com is very intrusive and anything but benign. In this instance, I don’t see it as that big a deal. One of the attractions to ShareThis.com was its WordPress plugin making setup as easy as going to the website to generate the widget code, then inserting that code in the settings box on the admin screen in your WordPress blog. But it didn’t work.
At ShareThis.com, a publisher generates a script that looks like this:
<script type="text/javascript" src="http://w.sharethis.com/button/sharethis.js#publisher=abcdefgh-ijkl-mnop-qrst-uvwxyz012345&type=wordpress&embeds=true&post_services=facebook%2Cdigg%2Cdelicious%2Cybuzz%2Ctwitter%2Cstumbleupon%2Creddit%2Ctechnorati%2Cmixx%2Cblogger%2Ctypepad%2Cwordpress%2Cgoogle_bmarks%2Cwindows_live%2Cmyspace%2Cfark%2Cbus_exchange%2Cpropeller%2Cnewsvine%2Clinkedin%2Cfriendfeed&headerTitle=Thank%20you%20for%20sharing!"></script>
After updating, the code will have a 2nd publisher id appended to the end. With two publisher ids, ShareThis will not register your site nor collect statistics.
<script type="text/javascript" src="http://w.sharethis.com/button/sharethis.js#publisher=abcdefgh-ijkl-mnop-qrst-uvwxyz012345&type=wordpress&embeds=true&post_services=facebook%2Cdigg%2Cdelicious%2Cybuzz%2Ctwitter%2Cstumbleupon%2Creddit%2Ctechnorati%2Cmixx%2Cblogger%2Ctypepad%2Cwordpress%2Cgoogle_bmarks%2Cwindows_live%2Cmyspace%2Cfark%2Cbus_exchange%2Cpropeller%2Cnewsvine%2Clinkedin%2Cfriendfeed&headerTitle=Thank%20you%20for%20sharing!&publisher=a1b2c3d4-ijkl-mnop-qrst-u4w2y10a2r4d"></script>
After reviewing the plugin code, I realized the way ShareThis generates the script must have changed overtime. Crowd Favorite wrote a great plug-in but it expects the publisher=xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx to be at very end and if it does not find a publisher id at the end, it puts one there which is why you will end up with two publisher ids. To fix this, simply move the publisher id to the end of the script before pasting the code into the ShareThis settings box in the WordPress admin:
<script type="text/javascript" src="http://w.sharethis.com/button/sharethis.js#type=wordpress&embeds=true&post_services=facebook%2Cdigg%2Cdelicious%2Cybuzz%2Ctwitter%2Cstumbleupon%2Creddit%2Ctechnorati%2Cmixx%2Cblogger%2Ctypepad%2Cwordpress%2Cgoogle_bmarks%2Cwindows_live%2Cmyspace%2Cfark%2Cbus_exchange%2Cpropeller%2Cnewsvine%2Clinkedin%2Cfriendfeed&headerTitle=Thank%20you%20for%20sharing!&publisher=abcdefgh-ijkl-mnop-qrst-uvwxyz012345"></script>
Note: In the settings box, the & will be converted to just & but the code correctly uses & with the post. Your code will still be xhtml compliant.
good