There’s a new version of ShareThis out this evening. This release fixes a bug in version 2.2 where the ShareThis button might not be visible correctly if your WordPress theme shows post excerpts on certain pages.
ShareThis is a plugin that makes it easy for your visitors to share your content to other people or online destinations and social web sites. You can see it in action by clicking the ShareThis link at the bottom of any of the posts or pages on this site.
The download and more information are available on my WordPress Plugins page.
If you have any trouble with this, please open a thread in the ShareThis Support Forums and the team will be happy to help you out.