So, we needed to look at, as well as writing full annotations for runs, the ability to tag runs (and other entities) with keywords. Being as we are writing a web-based application, this is very web2.0.
For examples of tagging, look at de.licio.us, facebook or flickr.
In a nutshell:
Display tags already given to a run (I'll use this, but replace with entity).
Click to Add tags
Change display to an entry field which has the tags in it, a cloud of all tags which have already been assigned to runs, which you can click to add or remove from the entry field, and they highlight if already in the entry field,
and the clever bit - if the user starts typing into the field, it comes up with suggestions in another revealed field of tags from the cloud, sorted by the frequency the tags have been used, showing the ten most common for the current suggestions, changing as the user types more letters.
(You may have noticed here that we are trying to get the users to essentially try to use the same tags again and again, rather than stick in a hyphen, etc)