The custom tags feature allows you to append custom tags to the vote URL. These tags will then help identify a vote in the poll reports.
A custom tag is data relevant to you that you want to associate with a particular vote (e.g., a customer reference number, email address, name, etc.).
So, if you wanted to add the following custom tags …
customer_ref : 101
email : firstname.lastname@example.org
gender : male
… you would populate the array variable pd_tags.
The tag data will appear in the vote analysis report.
When you export the data from the poll report, the tags will be included. This offers another method of filtering through the vote data based on the values of the custom tags.