Thanks for the feedback! This is something we thought about, but so far haven't done because we don't have a good way to verify that these blurbs would be real.

When using a blurb from a recommending Substack, we know that the original author wrote it. If we allowed users to put in custom blurbs, we unfortunately don't have a way to validate that it's not completely made up, which might devalue the feature.

That said, we're definitely thinking about a good way to do this, and I'd be all ears if you have ways you'd like to see this feature work in mind.