Summary: When you drive traffic to your website from a specific ad or source, make sure you are directing this traffic to the specific topic on your website. These topics-specific pages are also know as "landing pages" or "targeted landing pages." Recall that a "landing page" is the term for the first page that a visitor sees on your website (remember, it's not always the home page).
Whenever I lecture at a conference I always send my contact at the conference a gift from Godiva as a show of appreciation for their assistance. Thus, Godiva always sends me emails about specials, etc. Let's walk through one of these emails and use it as an example to explain targeted landing pages (I do this in my lectures but we can easily do it here in writing).
1) Godiva sends me an email about their new "Super Chocolate" product.
2) I open the email (so Godiva now knows I'm interested).
3) I read the email and click the link to "learn more" about the Super Chocolate product.
Now when I click that link, what page am I sent to?
a) the home page
b) the page about the "Super Chocolate" product
The answer is B!
And here's why -- from my actions with the email, it's clear to the marketers at Godiva that I'm interested in learning about the Super Chocolate product (I opened the super chocolate email, and I clicked on the link in the super chocolate email). Thus, they want to do everything possible to put the Super Chocolate product in front of me as easily as possible -- and the way they do that is by sending me to a targeted landing page about Super Chocolate. Now, it may be a landing page with a special offer, or simply a page about the product, but either way, they are going make it easy to learn about the Super Chocolate but putting the information right in front of my nose.
The alternative would have been to send me to the home page, and let me fend for myself in trying to find the page about the Super Chocolate. Now I'd have to figure it out - would it be under Chocolate? or New Products (I'm making these up - I haven't check Godiva's actual navigation) -- but you get the idea.