View or search your contacts
Click the contact list name or click Search in the Actions button
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This will open the contact list preview and search page
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Click the Add Rule button to search your contacts attributes, for a more in depth explanation on Search Rules see segmenting
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Click the + sign to add additional search criteria
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Tag contacts by entering the tag name, selecting the contacts, and clicking "Add Tags"
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Remove tags from contacts by selecting "Remove Tags" from the multi-function button drop down