I began editing Wikipedia sometime in 2008. However, until late in 2011, I edited exclusively under IP addresses. My primary efforts during this period were minor maintenance and drive-by sourcing of articles, often reached randomly. I kept no particular record of my anonymous work. My intention was to edit anonymously while getting a feel for the project's policies and procedures as well as its technical aspects, such as formatting and templating. I delayed the transition to a registered editor for far longer than I should have, over concerns that I would be looked upon with suspicion because "new" editors are not customarily familiar with Wikipedia processes and jargon. However, not everything can be done as an IP editor, I have come to regret having no record of my prior work in the project, and, of course, I have nothing to hide.
I am arguably a subject matter expert regarding certain aspects of operations research and queueing theory. However, in order to avoid potential conflicts of interest, I do not contribute directly to Wikipedia articles related to these topics. Luckily, Wikipedia is a big place, and there are no shortage of other topics to explore and develop.
Perhaps my favorite area of the project these days is volunteering as a reviewer of Featured Article candidates. I'm self-admittedly something of a "hard judge" there, especially regarding comprehensiveness, source reliability, and picayune matters of reference formatting. I think that Wikipedia's FA process is something to be proud of—evidence that crowdsourcing can work to produce not just informative material, but accurate content held to high standards of professionalism.