In practice, they have the Google home page to promote it...which is perhaps the only thing that can make a dent against something like IE which comes with the OS.

It will likely affect Mozilla, though for the moment it doesn't look like it, since they have extended their partnership for 3 more years. http://news.cnet.com/8301-1023_3-10028096-93.html .Though it will be interesting what will happen in that time.