Timing's blacklist feature lets you prevent specific app activities from being tracked.
Simply specify rules for the activities you do not want to be tracked, and Timing will ignore them in the future.
The rule format is the same as for project and filter rules, so the same documentation applies for the blacklist.

Blacklisting incognito web browsing activity

If you are surfing with Safari or Chrome in an incognito window, Timing will discard that window's title and URL and replace them with just a title of "Private".
So if you'd like to prevent time spent in incognito windows from being tracked at all, simply add a rule like "Title is equal to 'Private'" to the blacklist.

If you'd rather have Timing track your incognito browser windows like any other window, enter the following command in a Terminal window:

defaults write info.eurocomp.TimingHelper treatPrivateActivitiesLikeNormalActivities -bool true

Note: The blacklist will not apply to existing app activities — only future ones! In addition, the Blacklist screen only lists apps that Timing has tracked at least once.
Note: An improperly configured blacklist can cause Timing to not track any activities whatsoever!


Excluding activities with a specific keyword from being tracked

Excluding Mail and Safari from being tracked

Tracking only Mail and Safari