What am I?
Cipher
My last three letters serve to clarify.
her, is a pronoun - used to clarify referents, without using names.
My first four letters are where famous people speak.
CIPH (Collège international de philosophie). Yeah, famous people spoke there. Lectured, taught, and thought as well, probably. Yay for acronyms!
Dropping all consonants, I am almost a curse.
ie, ie... Fie! fie, a curse upon thee! if only the vowels are 'almost' a curse means they need a little more. The addition of 'F' makes a fine, traditional curse.
Hint
The hint from the comments, "Gur fbyhgvba rkcynvaf ubj gur evqqyr zhfg or zbqvsvrq gb lvryq gur fbyhgvba" translates to "the solution explains how the riddle must be modified to yield the solution".
What must we do to the riddle to find the answer? outthink it, puzzle through it, or cipher it - a word which means to encode, but also to solve problems! As a bonus, it is also how the hint is found.