I noticed a question, Is there a thesaurus which takes more than one word as an input? and I read it trying to understand why it was on meta. After I read it, I noticed that it doesn't suit on meta because it's not a question about the main site; if it were a question such as "When citing a source in my answer, how should I cite it?" then it would be appropriate for the meta site.
The meta site is not a second class site where English questions that don't suit the main site are migrated; it's a site for questions about the main site. If a question doesn't suit the main site doesn't mean it suits another site (including the meta site); it doesn't mean the question necessarily needs to be migrated to any site (as many closed questions show).
Questions about posts seen on the main sites are fine on meta, as any question about features seen (or desired) in the main site is.