Which fields can you prepare for a list to import to Twitter for paid marketing? According to Twitter Ads documentation, you can reference:

• Email addresses
• Mobile Advertising IDs
• Twitter @handles
• Twitter user IDs

There are pros and cons to each identifier. Here are their benefits and shortfalls:

1. The email address is probably the most readily-accessible point of data, the one you may already have at hand. However, the email you have for a prospect may not match the email address that Twitter has for that particular person who you're trying to reach. For example, you may have their business rather than their personal address. The disparity between the two emails is a question of "match rate," which I'll endeavor to address in a future post.
2. Mobile advertising IDs are device-specific. Google writes, "in mobile apps, there are no cookies... Typical advertising IDs are AdID (Android) and IDFA (Apple)." So, it's exact targeting, which is particularly well suited to app download campaigns as well as cross-device attribution. The downfall with using these is AdIDs are resettable, so your information may be out of date. Also, even if these are constant, they're only part of a conversion path that may take place on other devices than the one the id references.
3. Twitter handles (e.g., @ronkagan) are pretty good identifiers for advertising purposes. However, Twitter usernames can also be changed.
4. Users cannot change their user ids, though. These are essentially the account ids that Twitter assigns users when they sign up for service. So, email and username can each change, while id remains constant.

When we're advertising on Twitter, we want to be able to target the right users. Out of the four options, the id number is best. So, the question is, how do we retrieve the twitter id for a given user?

One way is by brute force. You can query each username in a variety of online sites that will ping the Twitter API for you and reveal the number we want.

There are, however, two programmatic (semi-automatic) ways to get the user ids of the prospects:

1. You can sign up for a Twitter developer account and teach yourself how to use your machine's Bash terminal to do batches of up to 100 cURL requests (the Twitter endpoint is rate-limited). Going this first route requires some knowledge that's typical of a data analyst or a software developer.
2. If you're comfortable with Excel or Google Sheets, you can use a paid service like Blockspring to query a hundred of your prospects at a time within your spreadsheet. While it's good to learn how to do a cURL request and know how to go about the first route, this is a not too expensive way to get what you need relatively quickly. Here's a demonstration of Blockspring and Twitter.