If the advertisers can see the MAID for each ad impression, then there's no need to be too specific about who you target - it'll just cost you more. On the othe

If the advertisers can see the MAID for each ad impression, then there's no need to be too specific about who you target - it'll just cost you more. On the other hand, if the advertiser doesn't get to see the MAID-per-impression, then the easy solution is to supply your one target MAID, plus another 999 bogus MAIDs (or, if the platform verifies that MAIDs are accurate before allowing you to use them, then you use 999 MAIDs from Liberia or some other country that your target won't visit).