Madison police apparently have a database of people who have exhibited strange behavior, the database maintained mainly for the safety of police officers if they need to make contact with the people on the list, but also as an unofficial record of people who might be dangerous.
What a horrible paragraph that is destined to creep people out about big brother. Let's take it apart piece by piece. First, they never should have used "apparently." They are journalists, and they should have asked a question or two that eliminated the need to use apparently, which is vague and uncertain for a story of this type, and thus allows the reader to create false impressions. An opinion piece can use apparently, a news story should only very rarely use it.
Second, if they are talking about what I think they are talking about, it is an in house contact management database that all departments keep, not some mysterious database that tracks your behavior. It really would be little different in action than the contact management databases that the Capital Times reporters and advertising sales reps use to keep track of their own contacts. This contact database allows the department to have an institutional memory of previous contact that they have had with individuals so officers can better prepare for future contacts. The notes in there might run from a mundane complaint to criminal activity.
That one paragraph is an example to me of how unprofessional the Madison media has been at times during these murder cases. They have every right to hold the Madison Police Department's feet to the fire, but for God's sake, report responsibly. Already in the comments to that story people have picked up on the mysterious strange behavior database and think that it is something that it really isn't.