You're thinking of the Affero GPL (AGPL), which triggers the reciprocity clause on modification for network services. The Lesser GPL (LGPL) limits the reciproc

You're thinking of the Affero GPL (AGPL), which triggers the reciprocity clause on modification for network services. The Lesser GPL (LGPL) limits the reciprocity to the code itself, provided you're only doing dynamic linking or equivalent and not melding the code into yours (i.e. static linking).