Hi @Hamish,
the documentation is a bit misleading. Actually you need two attributes.
Content
Name: data-balloon
Value: Your content goes here
Position
Name: data-balloon-pos
Value: top | top-left | top-right | bottom | bottom-left | bottom-right | left | right
There are two more Attributes you can use:
Change the size of the tooltip
Name: data-balloon-length
Value: fit | small | medium | large | xlarge
Enable word-break and white-space: pre-line (use together with data-balloon-length)
Name: data-balloon-break