A landing page (in fact, every page) can only cause one of five actions:
- Get a visitor to click (to go to another page, on your site or someone else's)
- Get a visitor to buy
- Get a visitor to give permission for you to follow up (by email, phone, etc.). This includes registration of course.
- Get a visitor to tell a friend
- (and the more subtle) Get a visitor to learn something, which could even include posting a comment or giving you some sort of feedback
I think that's the entire list of options
So, if you build a landing age, and you're going to invest time and money to get people to visit it, it makes sense to optimize that page to accomplish just one of the things above. Perhaps two, but no more.
When you review at a landing page, the thing to ask yourself is, "What does the person who built this page want me to do?" If you can optimize for that, you should. If there are two versions of a landing page and one performs better than the other, use that one!
Landing pages are not wandering generalities. They are specific, measurable offers. You can tell if they're working or not. You can improve the metrics and make them work better. Landing pages are the new direct marketing, and everyone with a website is a direct marketer.