The production of additives such as *too* has been argued to be obligatory if the immediate context contains a suitable antecedent such that the presupposition triggered by additives is satisfied. Similarly, additives have been claimed to full discursive functions such as highlighting parallelism between utterance content. With two production experiments we investigated the potential obligatoriness and discursive functions of additives, by manipulating the antecedents' salience focusing on the factors Similarity and Turn Distance. We furthermore explored whether the use of additives can be understood as a move to converge (i.e. socially align) with the antecedent speaker by investigating if speakers would omit additives when an additive might signal alignment with an impolite antecedent speaker. Overall, our results of experiments I and II suggest that while the production of additives seems to depend on the antecedent's salience, additive production was not as frequent as expected if additives were indeed obligatory. More specifically, our findings suggest that (i) in alignment with previous results on similarity, speakers tend to utter additives more frequently when their utterance's content matches the content of a previously formulated utterance; and (ii) speakers use additives more frequently when the matching utterance directly precedes their utterance. Furthermore, results of experiment II suggest that (iii) speakers deliberately drop the use of additives when wanting to diverge from an impolite speaker. Our findings lend support to models in which speakers use additives as a grounding tool to organise the discourse and maintain discourse coherence.