Ok I'll check out the lite version, it says Lite (Archive) so that didn't click with me that it was the text-only version.

Some of the search features that are hosted externally (like Google site search) can include taxonomies and ontologies that take care of word partial matches and text breaks so that if you search for "AD" would not do partial matches. Mostly they just spider all the posts in the forum and index them off-server so that the load is minimal on the server (except during spidering) but I understand your concern - hosting ain't free and resources are never unlimited!

I was hoping that add-ons/extensions/etc for the MyBB existed to do some of that stuff, but I wasn't going to put effort into researching if there was no interest.

Thanks!