Make rankings of:

-Top viewed articles
-Top viewed categories
-Top viewed tags
-Top viewed autor pages (blogs)
-Top commented articles
-Most voted articles (optional: define a rating)
-Most downloaded attachments

Combine the list above with any of the possible filters:

-Current category articles
-Current category (and its children categories) articles
-Current tag articles
-Current autor articles
-Current article attachments
-Specific category articles
-Specific category (and its children categories) articles
-Specific tag articles
-Specific autor articles
-Specific artible attachments
-All category/article/tag/autor (equivalent to no filter)

Additionally, optionaly filter by user options:

-Current vieweing user (actions done only by that user)
-Specific user (actions done only by that user)

And, of course, combine the two lists above selecting your desired timeframe, in the "relative time" mode:

-Last hour
-Last 6 hours
-Last 12 hours
-Last day
-Last 3 days
-Last 5 days
-Last week
-Last 2 weeks
-Last month
-Last 6 months
-Last year
-All time

Or in the "absolute time" mode:

-Today
-Yesterday
-This week
-Last week
-This month
-Last month
-This year
-Last year

Show evolution of:

-Article views
-Category itemlist views
-Tag itemlist views
-Autor itemlist views
-Article comments
-Article votes

Combine the list above with any of the possible filters:

-Current category/article/tag/autor being shown
-Current category to which current article belongs
-Current category (and its children categories) to which current article belongs
-Current autor to which current article belongs
-Specific category/article/tag/autor
-Specific category to which current article belongs
-Specific category (and its children categories) to which current article belongs
-Specific autor to which current article belongs
-All category/article/tag/autor (equivalent to no filter)

Additionally, optionaly filter by user options:

-Current vieweing user (actions done only by that user)
-Specific user (actions done only by that user)

And, of course, combine the two lists above selecting your desired timeframe, to complete the chart's x-axis to show the items evolution:

-Last X days (define the number of days you want to consider)
-Last X months (define the number of months you want to consider)

-IP geo-location: make Map charts of your visitors when they look at K2