You might try email marketing, social media marketing, or even digital advertising for your forums but unless your forum ranks on search engines and gets traffic from searching any marketing method you does not make any sense.
Yeah, I try to mix things up a bit each year instead of sticking to the exact same strategy. Trends change, so it makes sense to adjust really and like focusing more on short-form content, communities, or whatever people are actually using at the time. That said, I don’t change everything. If something’s already working (like SEO or email), I keep it and just build on it. It’s more about tweaking and testing new ideas alongside what’s proven, rather than starting from scratch every year.