What would be the purpose of/reason for moving back to a different url? If its been a few years, I’d leave it alone unless you watched everything decline since moving to the main url. Moving the forum to a new url now would probably be a bit chaotic, not only for your main url but for the forum itself…. Only reason I could imagine myself moving the forum in this scenario would be if all those links were really awful and unrelated to the url it currently sits on…
Linking to a page with actual key-phrases in the link help a great deal in all search engines when you want to feature for specific key terms. For example; “SEO Scotland” as opposed to https://www.hobo-web.co.uk or “click here“. Saying that – in 2019, Google is punishing manipulative anchor text very aggressively, so be sensible – and stick to brand mentions and plain URL links that build authority with less risk. I rarely ever optimise for grammatically incorrect terms these days (especially with links).
Everyone knows intent behind the search matters. In e-commerce, intent is somewhat easy to see. B2B or, better yet, healthcare, isn't quite as easy. Matching persona intent to keywords requires a bit more thought. In this video, we'll cover how to find intent modifiers during keyword research, how to organize those modifiers into the search funnel, and how to quickly find unique universal results at different levels of the search funnel to utilize.
However, that’s totally impractical for established sites with hundreds of pages, so you’ll need a tool to do it for you. For example, with SEMRush, you can type your domain into the search box, wait for the report to run, and see the top organic keywords you are ranking for. Or, use their keyword position tracking tool to track the exact keywords you’re trying to rank for.