About half the congregational sites I’ve visited today do not offer an RSS feed. And not much is happening on them either, so an RSS feed wouldn’t do much good. Probably, most are using closed proprietary sites, which is sad. Several congregations I looked for have no domain of their own.
Remember: Some of your friends and possible contacts are on those sites, but not all. Don’t invest in what isn’t yours, in what others will manipulate.
Do something that everyone can access. Reach out to all, not to a select group. Be available to anyone who is searching.