Snap Shots

Snap Shots, formerly “Snap Preview Anywhere, enables anyone visiting your site to get a glimpse of what other sites you’re linking to, without having to leave your site. By rolling over any link, the user gets a visual preview of the site without having to go there, thus eliminating wasted “trips” to linked sites. “

This is automatically turned on for every WordPress.com blog. If for whatever reason you dislike it, you can disable it for your blog under Design > Extras (this will turn Snap off for you and for your readers).

If you never want to see it again anywhere in the world on any site click on the options link in the preview box and they have a link that sets a cookie so it won’t show up anymore (this will only turn Snap off for you, not for the readers of your blog).