Most people access content through a search engines and social media.
People spend a lot of time on Facebook and YouTube.
Other than a very few exceptions, the concept of web portals is over (i.e. no one will start with your company page...not even you).
People don't use address bars and bookmarks as much as they used to.
The point: You can't expect your customers to visit corporate or product sites like they used to. These types of sites, more often than not, are in place now as a necessary backup. If at all, you can only expect your customers to visit your corporate or product site once and most of those visits will not go through your gateway. This is part of the reason why blogs, including Twitter, can easily be more relevant to a company or product than a corporate site or product site.