WhosOn Client 16.3 for Mac could be downloaded from the developer's website when we last checked. We cannot confirm if there is a free download of this app available. The software belongs to Communication Tools. This free Mac app was originally designed by Parker Software Ltd. We recommend checking the downloaded files with any free antivirus.
From the developer:
WhosOn Client adds live chat to your web site to engage with your customers. You can chat to your website visitors while they browse, to help increase sales and customer satisfaction. Proactive invites allow you to target a website visitor manually and engage them in a live chat, based upon their activity across your website. The WhosOn Mac Client allows you to view real time visitor activity and to take chat requests.
You may want to check out more Mac applications, such as eM Client, Parallels Client or ArraySync Client, which might be related to WhosOn Client.