Upon the launch of a new site - add big slide-down / lightbox explanation?

Question

Upon the launch of say a new social media site - is it appropriate to do a big slide-down / lightbox to explain what the site is about - or to let users figure things out for themselves?

Former:

• Leaves no room for confusion
• A sense of desperation - "we're new, please help us out!"
• Should provide an easy exit plus cookies so it doesn't repeat itself for existing users

Latter:

• Will act as if the site's already well-established
• Greater psychological impact (i.e. learning by doing as opposed to being told what to do)
• Users might get the sense that "this must be a new trend, I need to catch up" and start using it immediately

Answer 1

If you need it to start, you need it ALL the time -- none of this "upon launch" nonsense. Not everyone will find your site at the same time, and what's a good intro before will be a good intro later.

The real question you should ask is "Do I need [X] to explain the service?" If so, you're going to need it all along, and it's just a matter of whether or not you get out of the more experienced user's way. Doing something big like you're suggesting as an automatically triggered function is not necessary -- and can be annoying for more experienced users.

Answer 2

If you're talking about a big pop up as soon as a user loads your site, I would completely advise against it.

Unexpected pop ups associate themselves to bad advertisement practices and would most likely frustrate users.

I would much rather see a well presented header with a "learn about us" button or an introductory video.