When do I need a landing page service?

Many people seem to be very excited on "Landing Page services":
What is the Best Landing Page Service? (Performable vs. HubSpot vs. Unbounce vs. ??) I have already my webapp which does have a landing page (the first page). Now it seems to me people think on needs to use one of these tools. Do I use them besides my app or before the app launches? What are your strategies?

Unbounceable even speaks from a concrete number of visitors on my landing page. This confuses me. Were do the users come from? Why is this landing page better than mine?

You could do two things: use of the ones you mention or other external service, or make your own landing page. That is, your landing page shouldn't be your homepage or first page to begin with.

You can even make many landing pages, one for every campaign, or target, o whatever. Again, done either by you or other service. You can do many things with this: for example, measure the conversion rate for different landing pages which make an emphasis on different things, that way you know the way to go.

You should have a landing page because your homepage is not the best one to showcase your product. You show it there, but can do something nicer in a page made just for that. So that if have a campaign in google or facebook or whatever, you can direct your visitors to that particular page instead of the homepage.

Hope this helps you a little. I'm not the greatest expert either. Cheers.

It depends on what you want from your landing page. If you consider it as just the first page the site user experiences, then no, you don't need any tools.

If you consider it as the most important part of your site, and therefore wish to ensure you are maximising conversions (selling well), then you'll want to do a lot of testing, over a long time. That's when such a service becomes valuable.

http://visualwebsiteoptimizer.com/ is another such service, and claims to be the easiest to use.