Site owners actually have the option to make it close able, and implement with just a simple "help" button.
I think what generally happens is that the team that handles customer communication does not have the dev resources to get someone to add UI elements to their page, so only bigger companies take advantage of "closeable olark" and click to open the chat window.
We also found that once people close the window, many get confused and have a hard time opening it again. (clearly not a problem for the "average HN reader", who might clear cookies and reload)
I think what generally happens is that the team that handles customer communication does not have the dev resources to get someone to add UI elements to their page, so only bigger companies take advantage of "closeable olark" and click to open the chat window.
We also found that once people close the window, many get confused and have a hard time opening it again. (clearly not a problem for the "average HN reader", who might clear cookies and reload)