Personal branding is easily achieved by personal participation in relevant groups. The problem is that for a given topic there could be thousands of groups, each started by someone who wants a personal database of people to pitch to, albeit subtly. The groups have a lot of people who are not likely to be your customers, so persistent visibility will pay off.
The other way to remind your contacts that you exist is to post updates i.e. links to outstanding third-party articles and not your own content.