When I was on my college newspaper, I learned about the basic questions to answer in a news story - the 5 W's (who, what, where, why, when) and 1 H (how). The same can be said of therapy websites. Let me elaborate with my favorite pet peeve W - Where.
Now, what's a difference between a therapist's site and, say, a website for a service like telephone coaching, or for a web designer? The answer is our customer-base is local. Therefore, our sites are for a local audience.
It amazes me that I can visit a counselor's homepage, and not know where in the US they are located. This is a problem on a couple of levels.
First, I believe potential clients quickly orient themselves on a site (or don't) - to ensure the website they are on is what they were looking for - that this is in fact the right service (counseling) in the right place (their city). People may keep going if you don't meet these standards, but they tend to be easily dissuaded while surfing the web.
Secondly, think of how people are searching for a local service. They tend to be entering a city name in their search - otherwise they get results for all over the country. If your site doesn't have your city or town listed, the search engines certainly won't show your site in the results for a local search.
Coming next - More W's.....