SEO: "Fish Farming" - Patiently nurture fish, willing ones will bite.
SEM: "Gold Digger" - Spend money! Burn ads! Results are immediate.
CPC: "Pay Per Click" - Only pay when someone clicks your ad.
CPM: "Cost Per Mille" - Show your face a thousand times, whether seen or not, money is deducted.
CTR: "Click-Through Rate" - How many can't resist clicking? Fail if no one is hooked.
A/B Testing: "Head-to-Head Battle" - Two versions compete, the better data wins.
Retargeting: "Haunting You" - Didn't buy? Ads will chase you.
So what does the boss care about?
Of course, it's ROI "Profit or loss?" - How many times can the investment multiply? It depends on the ROI.