Given that I feel certain affinity to the #xl8 hashtag, I felt it my duty to check up on it. See how it's doing.
Turns out it's doing quite well, and the usual Twitter rules do apply to it also (even if they may be self-fulfilling):
Peak activity, then, comes just before mid-week, with just over 3000 tweets being made in the last 30 days. The all-time tweet-count stands at over 24k #xl8 related tweets. 
Finally, in the last 24 hours, 300 #xl8 tweets reached around 87,000 followers, giving around 270,000 impressions (including retweets). 
This can all be taken with a pinch of salt, but the bots have been out scouring the Twitter API and these are the results as best they can be gleaned from a short between-jobs research run.
 source: http://analytics.topsy.com/?q=%23xl8 and http://topsy.com/s?q=%23xl8
 source: http://hashtagify.me/#xl8
 source: http://www.hashtracking.com/fast-report/?hashtag=xl8