Thanks for the help. I took a look at my blog on another computer and saw the sharing buttons that way; it must be that they don't show up when logged into the blog as an admin.
The plug-ins that are currently activated are:
Akismet
All in one Favicon
All In One SEO Pack
Dagon Design Sitemap Generator Plus
Extended Comment Options
Fast Secure Contact Form
Google XML Sitemaps
IntenseDebate
Jetpack by WordPress.com
podPress
Polldaddy Polls & Ratings
Quick Adsense
Twitter Follow Me Box
Ultimate Google Analytics
VideoPress
WordPress Hashcash
Wordpress Video Plugin
WP-DBManager
As I look at the list, I suppose I could eliminate some of them; a number were put in before Jetpack came along.