Performance notes: tested on a small WPMU install(>200 blogs). I have not seen how this version performs "maxed out" on my install yet(it should not be slower than the previous version, however). I do not know how this plugin performs in a large install. An array of "Blog_id, post_id" pairs are stored in usermeta->LatestComments to a defined maximum, called then sliced by page number, looped to retrieve posts, then each post looped to retrieve comments - "My Comments" and "Other comments". The bottom of the My Comments page has a numqueries count, FYI(if SiteAdmin). Redefining the MY_POSTS_APAGE constant can throttle the page.

Known Bugs: redefining the MY_COMMENTS_TRACKED constant to a lower limit after users have "maxed out" the previous limit will only unset one comment after each comment submit("update_usermeta(...)") thereafter. Such users will continue to exceed MY_COMMENTS_TRACKED Limit until they "dismiss" enough comments to be below the newly defined limit.

WPMU.ORG Plugin Competition eligibility note: this plugin is a significantly revised/enhanced/twisted version of WPMU-User-Comment-Tracking-and-DisplayThis work is Copyright GNU GPL You and Your Loved Ones. And: - Xiando (Oyvind Sather), who originally wrote it - And D. Sader - and is intended to add similar functionality(with a few twists) as Matt's popular wordpress.com My Comments feature. On that basis, I'd accept a decision by the judges to exclude this plugin from the contest.