What I do at Wikipedia
Mostly expanding and editing articles; in no specific subject areas. Most of my contributions have been recasting messy sentences, spelling mistakes and bad grammar. I've also created one or two articles.
My view of the strengths of Wikipedia
Not so far removed from the original concept. Clearly as an accessible knowledge base for all to edit and improve, it is a powerful concept. It allows the combined knowledge and expertise to be gathered in one place.
My view of the weaknesses of Wikipedia
Not the article vandals who come to spoil articles now and again, but very often some official editors who think they are entitled to the last word on everything. Another user on here User:GFHandel has a good point about the over-reliance upon citations. This spills over into the tiresome editorial demands for citations to every idea, suggestion, thought, implication...etc, which spoils the articles nearly as much as the unwanted contributions of article vandals.