Limitations of the Drupal 5 version

This module utilizes Views for producing lists of flagged objects. And here lies the limitations of the Drupal 5 version.

Listing only nodes

Views 1.x (Drupal 5) can only produce lists of nodes, or of things belonging to nodes. It can not produce lists of anything else. (It can sometimes give the impression it can, but it can't really do it.)

In other words, you can not produce lists of flagged users, or of flagged comments, using Views 1.x.

(Theoretically, it could have been possible with this module to produce lists of flagged comments in Views 1.x, but the Flag module doesn't support this.)

This limitation (and many others) were lifted in Views 2.x, which is not available for Drupal 5.

"So I can't flag, and I can't list, users in Drupal 5?"

You can! But not directly:

Drupal 5 websites usually use modules such as Bio or Node Profile, that create corresponding nodes for users. So you can flag these nodes. Views can easily produce a list of them.

Listing content which isn't flagged

Another feature possible with Views 2.x is listing content which is specifically not flagged. This is not supported in the Drupal 5 version of this module.

Controlling access to tabs

A feature this module will very soon support is selective display of tabs on nodes. For example, you'll be able to place a "Who's bookmarked this" tab on a node only if somebody has actually bookmarked it. Or place some tab on the user profile page only if that user is flagged somehow. This too is not supported in Views 1.x.