A Crowdskout ID is a unique identification number that gets assigned per profile in your account.
If you want to avoid duplicate records and have an immediate match when you import your data, try importing with Crowdskout IDs.
You can find the Crowdskout ID in the URL of a profile. It is the string of numbers that immediately follows "/profile/."
You can import your data through the import tool. Once you have a Crowdskout ID you can use the ID to avoid creating duplicate profiles. Additionally, by matching via Crowdskout ID, the match is immediate.
For instance, if you have a list of Crowdskout ID's and you want to add additional information to these profiles -- such as new email addresses, donation data, phone calls etc. you can have a column of Crowdskout IDs followed by the additional data you wish to append to an existing profile.
The additional columns such as "Email Address," "Donation Date," "Donation Amount," and "Donation Campaign Name" in the example above will get appended to the existing profile.