If you're not quite ready to launch your website but you need something up for vistors to see, you're better off putting up a simple page with basic contact info than an incomplete site. “Under construction” and “Coming soon!” pages remind me of the frontier days of the web in the mid to late 1990's, where cheesy “under construction” graphics could mean anything from a week to several years before it's complete. It's not a whole lot, but it looks better than something that's not polished or complete. More importantly, it looks intentional and not just something thrown together. A bad site (or page) is worse than no site.