Is is just me, or am I seeing an awful lot of posts on Mastodon lately that are nothing more than thinly-disguised ads selling products or services?
The only ads/marketing I regularly see are for stuff like furry art, other physical arts/crafts items and specialist computers / electronics and the folk doing that are 100% honest and transparent about what they are selling.
If you are seeing "hidden" ads on mastodon.social timeline (or indeed, anywhere else) which fit into the category of spam marketing then report them - the mods *do* eventually take action about such things..