You'll notice in Crelate, that there are options for a last updated as well as last activity date.
The difference between the two will be outlined below:
Last Updated On: This will occur when a contact's profile is edited or changed. For example, adding or editing a column under the details section (ie. phone number, email address, education history), adding a candidate description, or adding a tag will update this field.
Last Activity Date: This will occur when a certain activity is logged on a contact record. Therefore, when logging certain activities, the activity date will change accordingly. You can additionally customize which specific activities merit an update to the last activity date column. This will allow you greater flexibility to still log certain activities without having them reflected in your last activity update. To customize this, you may go to Settings>> Activities>> Select the given activity>> Check the engagement box (see screen shot below).