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Codeproject is great for writing and publishing article, github/git is great for hosting code.
Do you ever evaluated some sort of integration?
For example instead of manually uploading a zip file you can provide a way to pull it from a git repo. In this way updating the source code can be really fast and easy.
A similar solution can be provided for article text (a markdown file inside the repository?).
I say this because I hate to always keep up to date my articles on codeproject (cleaning the project, zip it, uploading it, modify the link, ...). Usually I simply put a header that point to the official github repository and I never update it on codeproject.
One of the big issues with having 10M members is names. Everyone has a name, and most want to use their name, or at least something vaguely resembling it. The issue is that Real Names are messy, human things meant for messy human things, and are terrible as a way to label things in a way that makes it easy (for a programmer) to reference that name within text or in a URI. We can't have //www.codeproject.com/members/Chris Maunder because the HTTP spec doesn't allow spaces in URIs, nor can we confidently say Chris Maunder refers to me in text, because it could also refer to someone names Chris who is rambling incoherently[^].
So we have Display names as a way to label your content such as posts and articles, and we have usernames as a way to provide a human readable and programmer parsable handle to your account. //www.codeproject.com/members/chris-maunder as a link to you and @chris-maunder as a reference to you in messages.
You don't need to use @username and you can be safely ignore the feature if it bugs you. However, if you like the convenience then a member's username can be found on their profile page or in the popup that appears when you hover over their name in the forums (assuming you have "Profile Popups" enabled in the forums).