According to the National Association of Realtors, 42 percent of homebuyers start their home search online, and 92 percent use the Web during the home search process. While the Internet can be a good place to start looking, there are things real estate agents know about the process of buying and selling a home that can't be found in any Web browser.

Here are a few.

1. How to price a home

When setting a listing price, agents consider scores of factors, from local and national market trends and neighborhood development activity to the latest buyer preferences for kitchen appliances and landscaping. Every home is unique, and an agent with a track record of success knows how to price it attractively in the market.

The Internet isn't always much help when it comes to comparison shopping, either. Many of the same factors that help an agent set an appropriate listing price aren't available in an algorithm, so online estimators aren't always accurate – and could be costly if you purchase without consulting a real, live professional.

2. Marketing offline

While online marketing can certainly be valuable, agents have networks of contacts and years of experience to round out their marketing plans.

And, for buyers, agents often can tap into their network to learn about great properties before they hit the real estate websites or even the MLS.

3. Key points in the process

If you find a home you love online, the website won't be there to guide you through a mortgage application, find a home inspector or advise you what to do if an inspection reveals issues.

4. How to negotiate

Having an experienced, professional negotiator drive your transaction can be vital to reaching a fair price for the property you're buying or selling. A website can give you an estimate of how much a property should cost, but it can't evaluate whether that's a great price or not.