First of great plugin!
I do have a slight complaint/feature-request though.
Can you please make it possible to set "all" option defaults (weight, post types etc..).
as i understand it the plugin will only cache the related results if all options in a request match the defaults (bar limit ofc), i can understand why this is and it is perfectly sensible.
However if i wish to change the defaults, knowing that this will effect all general yarpp requests, i.e. to always include a custom post type or globaly adjust weighting, and still take advantage of the caching it should be possible.
I had to resort to altering the 'yarpp' option directly to achieve this as it wasn't possible to do it from the settings page.
not ideal since i have to do it before every yarpp request to ensure it hasnt been overwritten by the settings page or via an update etc.
i appreciate it would be tricky to make a settings page that would incorporate all options without making it very complicated for the general user but perhaps you could have it load defaults from a php file in your theme. 'yarpp-defaults.php' for example if it exists.
oh and one other thing, i don't know if its just me but i had issues with yarpp not loading the default stopword list because it checks to see if WPLANG is defined and my wp-conf contained
which i believe is the default on a clean install, this results in no file being loaded as it is defined but as an empty string, removed the define and all worked as expected with the en_US list loaded.
keep up the great work.