Is Twitter useful to architects?
Unlike business cards or a logo, which every architect can relate to as a marketing tool, it is not so clear where Twitter fits into an architect's business development toolbox. I think this will provide a little clarity. Let's start with some PROs and CONs for Twitter.
The key to benefitting from Twitter is whether or not you are publishing your own information about your area of expertise. If you aspire to be recognized as a thought-leader in your specialty, Twitter can enhance the perception you want to build. It can also harm the perception you want if your followers don't see a stream of new information coming from you. So whether you use Twitter or not depends on whether you are publishing worthwhile content regularly.
For content to be worthwhile it has to tell your audience something they would like to know about a topic that they care about. Even a mundane specialty, say school design, can do this. But a generalist will struggle to find a topic that appeals. A strong specialty, say cancer research labs, should have an easy time demonstrating expertise.
Are you interested in writing about your specialty in addition to practicing architecture? The actual writing can be delegated, but you will have to be involved to create the topics and manage the tone. Twitter can assist you in building a reputation, but you will need to do the heavy lifting of building a specialty, which is a very worthwhile endeavor on its own.