The DESCRIPTION line in the ebuild for xfce-extra/xfce4-smartbookmark-plugin reads "Smart bookmark plug-in for the Xfce desktop environment". Well, we know that! What we don't know is that through this you can send a web query, e.g. call a search engine. Please replace the redundant description with something more explanative.
It looks fine to me - a short oneliner explaining the basics. Note that DESCRIPTION has an upper limit of 100 characters. The longdescription tag in metadata.xml can be used for a more detailed description.
The current description looks fine to me, and I'm not a fan of maintaining longdescriptions for the plugins for features since you'd have to be constantly updating them when version changes This is what the HOMEPAGE is there for