Does the job well, excellent support

A slick, straightforward and highly manageable way of adding tooltip popups to sites. Very customisable: you can tell it only to highlight the first instance of a word or phrase on a page, for example, or to omit certain words or whole pages from pop-ups.

The tool also builds its own glossary, which can be extensively styled. The only drawback is that if this glossary page shows the definitions in full, then rolling over the titles pops up exactly the same definition as readers are already viewing – and there’s no way to turn this off for titles alone. Otherwise, an excellent tool with terrific customer support.